Search

A compact size, dual-band rectangular spiral antenna with an inset feed is simulated and tested for S-band applications. Feeding of an antenna is given through a 50Ω microstrip transmission line. The proposed design consists of a rectangular spiral radiating patch in the top plane and a Z-shaped structure in the bottom plane. Ansoft HFSSv13 has been utilised to design the rectangular spiral antenna, and parametric analysis has been done to verify the characteristics of an antenna. The rectangular spiral antenna is fabricated by utilising chemical etching, and it is tested by utilising MS2037C Anritsu combinational analyzer. Reflection coefficients of -16.5 dB and -16.2 dB, and fractional bandwidths of 8% (2.35-2.55 GHz) and 6.7% (3.22-3.44 GHz) are obtained at 2.4 GHz and 3.3 GHz, respectively. Maximum gains of 3.1 dBi and 3.34 dBi are obtained at the two resonating frequencies. Omnidirectional and dipole type radiation patterns are obtained for different values of θ and Φ. The rectangular spiral antenna occupies an area of 16×16×1.6 mm³, and it is fabricated by using FR4 material. Simulated results are in good agreement with the measured ones. These results make the antenna suitable for many Zigbee/IEEE 802.15.4-based wireless data networks that operate in the 2.4-2.4835 GHz band, and it is also suitable for a wide range of applications including FWA systems. [ABSTRACT FROM AUTHOR]

The proposed research work presents a design of dual-band, beam-steering antenna array with feed network and E-shaped radiators. Two different design schemes has been proposed for 5G applications. This paper presents a detailed design procedure, a prototype, including the array and a planar feed network, for the second scheme. This array is capable to generate more than 22 beams in different directions depending on the ON/OFF state of PIN diodes (MA4SPS402) used in the switched line phase shifters. The scanning range covered by this array is −45° to +45°. To cover the entire 360o range, four such array prototypes are sufficient. To enhance the directive characteristics of the array, inter-element spacing is optimized with D1 = 86 mm and D2 = 40 mm. Maximum directive gain is 14.4 dBi at 3.6 GHz and 11.7 dBi at 2.4 GHz. Return Loss obtained is −24.89 dB at 3.6 GHz and −13.79 dB at 2.4 GHz. In order to operate the array in two frequency bands, the Slot antenna is designed using Quarter Wave Transformer with Directive Gain of 7.6 dBi and 7.39 dBi at 3.6 and 2.4 GHz respectively. Feed network for this second array has been designed using Wilkinson Power Dividers and Switched Line Phase Shifters. When the frequency of the excitation signal is 3.6 GHz, the maxima will be in the positive direction and when it is 2.4 GHz, it will be in the negative direction for the E-Plane. Beam switching, which is based ON/OFF state of the phase shifters will be in the H-Plane for both frequency regions. [ABSTRACT FROM AUTHOR]

This paper presents a 2-port MIMO antenna with a CPW feed, designed for dual-band operation with high isolation. We resolved bandwidth and polarization issues in the antenna's initial CPW-fed design by modifying the radiating patch and incorporating an asymmetrical ground plane. These adjustments enabled dual-band and dual-polarization functionality. The first band, with linear polarization, operates between 2.75 GHz and 2.86 GHz for sub-6 GHz wireless applications, while another band exhibits circular polarization with wide-band resonating at two frequencies, in the (4.7–5.6) GHz and (7.1–8.5) GHz ranges, respectively, covering the entire C-band and suitable for wide-band applications. The antenna, built on a Rogers-5880 substrate (1.57 mm thickness, εr = 2.2, tan δ = 0.0009), offers low loss and excellent thermal stability. The antenna, measuring 45.5 × 27 × 1.57 mm3, attains port isolations of 27 dB and 22.4 dB, with peak realized gains of 2.8 dB and 5.4 dB in the two bands. Furthermore, we analyze the key performance of the MIMO antenna, including the envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), and channel capacity loss (CCL), and confirm that they fall within an acceptable range, making it an excellent choice for many portable wireless applications. [ABSTRACT FROM AUTHOR]

This paper reports design and results of a microstrip patch antenna for broadband application in the millimeter wave communication with multiband features. Electromagnetic solver high-frequency structure simulator (HFSS) is employed to measure the effectiveness of the electromagnetic properties and electrical behaviour of the antenna. The proposed microstrip patch antenna (MPA) can be easily fabricated on a single substrate using standard photolithography process to attach the radiating element and feed lines to the dielectric material. On a 4.93 mm*5.86 mm metallic patch, over FR4 epoxy substrate with dielectric constant 4.4 and loss tangent 0.03, two L-shaped slots are placed along with a few micro slots of varied dimensions, and the antenna is fed with microstrip feedline with resistive load termination of 50 fi. Pentaband resonant frequencies are realized in the K-band at 13.6 GHz, 23.2 GHz, 29.68 GHz, 32.96 GHz, and 38.56 GHz, with minimum return loss of -23.17 dB, bandwidth 2.32 GHz, omnidirectional radiation pattern, and maximum reported gain of 4.5 dB. The designed antenna achieved good electromagnetic radiation properties and electrical behaviour, and is a good choice for broadcasting over short distances, surveillance and monitoring, wireless sensor backhauls and telecommunication in the K-band networks. [ABSTRACT FROM AUTHOR]

An ultrawideband slant-polarized monopulse feed is designed and fabricated for microwave applications. The proposed configuration features four end-launched diagonal horns allowing for the production of sum and difference channels in two principal planes. The key advantage of this proposed monopulse antenna over traditional monopulse feeds is its ability to combine the benefits of ultrawideband performance with slant polarization while maintaining acceptable side lobe level. The design is validated by fabricating a prototype of the proposed feed antenna. Measurement results are in a reasonable agreement with the simulations. The measured ratio bandwidth is 2.5:1 from 8 to 18 GHz with a peak gain of 17.92 dBi. The null depth in the difference patterns is approximately − 32 dB. Given these characteristics, the proposed monopulse feed is a suitable choice for use in commercial tracking radar systems that require wide bandwidth and slant polarization, such as those found in satellite-based applications. [ABSTRACT FROM AUTHOR]

Summary: This research proposes a novel low‐cost aperture coupled elliptic patch nanoantenna which works best when it has a stable radiation pattern and good gain. On the upper portion of the substratum, a cross‐shaped hole was additionally engraved from a metallic strip with a silver composition. Elliptical‐shaped silicon material is employed as a patch in this antenna design which is made on a substrate made of inexpensive glass epoxy. The silver substance makes up the nanometallic strip line at the substrate's base. A cross‐shaped hole has also been etched from a metallic strip with a silver composition on the upper section of the substrate. As the foam substrate to be used in between the feed and antenna substrates, Rohacell was adopted. A proposed simple cross‐shaped aperture enhanced the bandwidth of the planned antenna without degrading its radiation performance and is loaded on a proximity‐linked elliptical microstrip antenna. To achieve the highest coupling, the lowest back radiation, the least amount of spurious radiation, and good efficiency, the patch and feed line are positioned in the middle, at a right angle over the slot. The proposed antenna was simulated in HFSS, and optimum results were observed from the output. The results were evaluated based on radiation pattern, return loss, smith chart, radiation efficiency, and 3D polar plot for 300, 500, and 800 THz frequencies. Also, the impedance bandwidth, gain, and a number of bands were compared with other conventional methods and our proposed method proved to outperform the existing method in all aspects. [ABSTRACT FROM AUTHOR]

In this paper a 5G compact antenna is investigated at 28 GHz. The structure is based on Quasi-Yagi antenna comprising a director, driver, and reflector. The SIW technology is utilized to feed the antenna because of its numerous benefits. The antenna array is designed and simulated and the S11, E pattern, and H pattern are analyzed for both single-element and array antennas. Moreover, the effects of various parameters such as the number of stubs, the length of the director, the distance between the director and driver, the length of the driver, and the distance between the driver and reflector on S11 are studied. The HFSS and CST software are used for all analyses. Additionally, for the array antenna the effects of increasing the number of directors on S11 and antenna gain, change in antenna length, and variations in distances between elements are evaluated. [ABSTRACT FROM AUTHOR]

This paper presents a novel multi-layer beamforming antenna array based on Fabry-Perot resonator that is excited by a high-performance compact 4 × 4 Butler matrix using substrate integrated waveguide (SIW) technology for X-band application. The adapted ring patch antenna is fed through the aperture on a rectangular SIW cavity and forms the radiating element in the antenna array. Enhanced characteristics of the antenna array are realised by inserting an electromagnetic bandgap (EBG) structure between the radiating elements and a superstrate constituted from two complementary frequency selective surfaces (FSS) that forms a Fabry-Perot resonator (FPR). Circular polarisation in the proposed FPR SIW antenna array (FPRSAA) is achieved by using a combination of sequential phase rotation and orthogonal feeding techniques. Measured results of antenna array (Ant. II) show |S11| ≤ −10 dB between 8–12.0 GHz, a circular polarisation (CP) gain variation between 15.64–18.54 dBic, 3 dB axial-ratio between 8.5–11 GHz, and scanning angle covering −47 to 47 degrees. [ABSTRACT FROM AUTHOR]

This paper presents a circularly polarized (CP) monopulse slot array antenna based on gap waveguide (GWG) technology. The proposed monopulse antenna is composed of a 4 × 4 array antenna fed by the monopulse comparator network in a compact three-layer structure. To achieve a broad axial ratio (AR) bandwidth of right-handed circular polarization (RHCP) in the sum radiation pattern, a septum polarizer is used in the radiating aperture. Based on this approach, horizontal transition structures are used to excite the radiating array from the WR-28 waveguide to the GWG, which helps to reduce the reflection loss and expand the impedance bandwidth. Experimental results show that the impedance bandwidth is 30.5 GHz to 40 GHz, which is 27.1%. The 3 dB AR bandwidth is 31%. The measured null depth is −40 dB, and the maximum measured gain in the sum pattern is 22 dBi at 34 GHz, while the antenna efficiency is greater than 86%. The advantages of low loss, broad bandwidth, and compact structure make the proposed antenna a competitive candidate for millimeter-wave (mmWave) monopulse direction-finding applications. [ABSTRACT FROM AUTHOR]

In order to achieve high accuracy in interferometric direction-finding systems, antennas with a stable phase center in the working bandwidth are required. This article proposes a miniaturized loaded open-boundary quad-ridge horn (LOQRH) antenna with dimensions of 40 mm × 40 mm × 49 mm. First, to stabilize the phase center of the antenna, the design builds on the foundation of a quad-ridge horn antenna, where measures such as optimizing the ridge structure and introducing resistive loading were implemented to achieve size reduction. Second, electrically small-sized antennas are more susceptible to the effects of common-mode currents (CMCs), which can reduce the symmetry of the radiation pattern and the stability of the phase center. To avoid the generation of common-mode currents during operation, a self-balanced feed structure was introduced into the proposed antenna design. This structure establishes a balanced circuit and routes the feedline at the voltage null point, effectively suppressing the common-mode current. As a result, the miniaturization of the LOQRH antenna was achieved while ensuring the suppression of the common-mode current, thereby maintaining the stability of the antenna's electromagnetic performance. The measured results show that the miniaturized antenna has a small phase center change of less than 20.3 mm within 2–18 GHz, while the simulated phase center fluctuation is only 14.6 mm. In addition, when taking 18.5 mm in front of the antenna's feed point as the phase center, the phase fluctuation is less than 22.5° within the required beam width. Along with the desired stable phase center, the miniaturized design makes the proposed antenna suitable for interferometric direction-finding systems. [ABSTRACT FROM AUTHOR]

In this manuscript the plasmonic flower shaped silver nano dipole antenna is investigated on the silicon dioxide substrate for the optical wireless communication. The nano-circuit modeling of the proposed flower shaped nano dipole antenna is discussed which will enable the design of nano-photonic chips. The resonance tuning of the proposed flower shaped nano antenna is exhibited through end-to-end stacking of the flower cells over a petal of the nanostructure. The various possible structures were designed to tune the frequency in the range from 170 to 271 THz which covers 1550 nm window of the optical communication. The gap tuned flower shaped nano dipole antenna is designed by controlling the optical coupling of the waves in between two dipole arms of the nano-antenna. Further the detailed investigation on the performance of the flower shaped nano dipole antenna is executed through the design parameters such as gap of the nano dipole antenna feed G and radius of the flower cell R. The optimum nano-antenna characteristics which are suitable for the optical wireless communication are observed at the resonance frequencies such as 270, 284.5, 260.5, 226.5 and 209 THz with reflection coefficients −42.17, −42.42, −42.17, −45.20 and −50.33 dB respectively. [ABSTRACT FROM AUTHOR]

Single antenna elements in wireless systems cannot meet the specific requirements. As a result, multiple-input multiple-output (MIMO) antennas are becoming increasingly popular in high-speed communication systems and are crucial to the development of wireless technology in the present day. But even though fifth-generation (5G) terminals can greatly expand channel capacity, achieving the best isolation in a small package is difficult. A triple band H-shaped slotted MIMO antenna is designed and tested for wireless communication applications. Feeding for a MIMO antenna is given through 50 Ω transmission line. H-shaped slots are subtracted from the microstrip patch and a defected ground structure has been used as the bottom plane for better radiation properties. Chemical etching has been used to fabricate the MIMO antenna and it is tested by using MS2037C Anritsu Combinational Analyser. Reflection co-efficient of -35.8 dB, -24.9 dB and -20.4 dB are obtained at 4.08 GHz, 7.3 GHz and 11.1 GHz respectively. 3 dBi gain values of 4.91dB, 6.52 dB and 10.53 dB are obtained at 4.08 GHz, 7.3 GHz and 11.1 GHz respectively. Omni directional and dipole type of radiation patterns are obtained for different values of θ and Փ. MIMO antenna occupies an area of 80 x 80 x 1.6 mm³ . To evaluate the performance of the proposed antenna in terms of its performance, it is compared with the previous literature highlighting the potential areas for requirement. Resonance was observed at 4.08 GHz, 7.3 GHz and 11.1 GHz with an isolation of -20 dB. Simulation results are in close agreement with the measured results. Several MIMO antenna parameters like TARC, MEG, CCL and DG were analyzed. These results make the antenna suitable for wireless communication applications. [ABSTRACT FROM AUTHOR]

This paper details the design, manufacturing, and measurement of a 37.33 mm × 87.2 mm x 1.6 mm high-bandwidth Cantor fractal slotted defective ground surface (DGS) antenna array (1x2) for the microwave C-band (4–8 GHz) and X-band (8-12 GHz). For exciting a patch antenna, a mutually coupled feed (a special type of corporate feed) is utilized. Mutually coupled feed comes into the category of non-contact feed. Non-contact feeding systems can be designed to minimize electromagnetic interference (EMI), particularly in high-frequency applications. It also avoids impedance mismatches and hence increases the bandwidth and gain. In this paper, the fringing effect has been taken into consideration for proper isolation between the feeding network and patch. This study also ensures minimal mutual coupling and interference between patches while maintaining a uniform radiation pattern. Operating bands of 7.05-8.53 GHz and 10.33–11.43 GHz are all compatible with this architecture. The suggested antenna has promising results in both simulation and measurement. For example, it includes a large impedance bandwidth of 1.48 GHz and 1.1 GHz and a reflection coefficient (S11) of -28.93 dB and -19.62 dB at its resonance frequencies of 7.6 GHz and 10.7 GHz, respectively. Additionally, this achieves a high gain of 10.05dBi at 7.6 GHz and 7.73 dBi at 10.7 GHz. While mutually coupled feed( a special type of corporate feed) is a well-investigated concept in literature, its use in antenna arrays is a novel aspect that has not been previously addressed. Furthermore, the application of cantor-inverted cantor fractal geometry on patch antennas has also remained unexplored in existing literature. This research investigates the implementation of mutually coupled feed in antenna arrays, demonstrating its feasibility and potential benefits while minimizing fringing effects through strategic feed placement. [ABSTRACT FROM AUTHOR]

An omni-directional H-shaped wideband microstrip circular patch antenna with an inset feed is simulated and tested for sub-6 GHz wireless communication applications. Excitation of the antenna is given through a 50 Ω feed line. Initially, concentric circular patch antenna is simulated with full ground copper plane and then after defected ground structure has been utilized to attain wider bandwidth. Parametric analysis of the H-shaped microstrip circular patch antenna is done by using HFSS, chemical etching has been utilized to fabricate the antenna and the antenna is tested by utilizing MS2037C Anritsu combinational Analyser. The simulated H-shaped microstrip circular patch antenna exhibits resonance at 3.0 GHz-4.5 GHz with S11 of -23.3 dB and with a gain of 3.067 dBi. Hshaped microstrip circular patch antenna occupies an area of 31 x 28 x 1.6 mm3 and to validate the antenna, it is fabricated by using FR4 epoxy material the simulated results are in good compact with the fabricated results and it is well suitable for N77 and N78 sub-6GHz applications. To evaluate the performance of the proposed antenna in terms of its performance, it is compared with the previous literature highlighting the potential areas for requirement. Resonance was observed at 3 GHz- 4.5 GHz with VSWR of 1.15, reflection co-efficient of - 23.3 dB and gain of 3.067 dBi. These results make the antenna suitable for N77 and N78 Sub-6 GHz wireless communication applications. [ABSTRACT FROM AUTHOR]

A novel wideband 4-port circular patch multiple-input-multiple-output (MIMO) antenna is designed at 1.76 to 9.06 GHz. The proposed antenna is fed by using microstrip feed and it is fabricated using FR4 substrate. This circular shaped patch antenna is applicable for WLAN and satellite communication applications. Each circular patch on the four corners is attached with a 50 Ω microstrip feedline. Radiation pattern of the antenna is obtained at 1.76 GHz, 2.4 GHz, 3.5 GHz and 9.06 GHz for different values of θ and Փ. Reflection coefficients of -16 dB, -22 dB, -24 dB, -15 dB has been observed at 1.76 GHz, 2.4 GHz, 3.5 GHz and 9.06 GHz respectively. To reduce mutual coupling and to enhance the parameters of the MIMO antenna Swastik shaped ground is embedded. To evaluate the performance of the proposed antenna in terms of its performance, it is compared with the previous literature highlighting the potential areas for requirement. Resonance was observed at 1.76- 9.06 GHz with an isolation of -20 dB. Proposed antenna is simulated by using finite element method tool Ansoft HFSS. The minimum proximity is observed between simulated and measured results. These results make the antenna suitable for wireless communication applications including satellite communication applications. [ABSTRACT FROM AUTHOR]

This article presents an approach to expanding the impedance bandwidth of a bilateral slotted antenna backed by a substrateintegrated waveguide (SIW) cavity using high-order radiation modes. By trimming a section of the conductive ground plane and connecting one side of the bottom long slot with a via, the three hybrid modes of the cavity are perturbed and merged to achieve a broad bandwidth. The optimized antenna is fed by a microstrip transmission line for Ku-band applications, demonstrating an impressive impedance bandwidth of 6.68 GHz (a fractional bandwidth of 41%) ranging from 12.82 GHz to 19.5 GHz, with a peak gain of 6.6 dBi. Compared to previous studies, the proposed antenna offers not only a wide bandwidth but also a compact size, with dimensions of 29.7 x 22 mm², and its electrical dimensions are 1.6λ0 x 1.19λ0, where λ0 is the free space wavelength at the center frequency fcenter = 16.16 GHz. Additionally, it has low production costs due to fabrication on an inexpensive FR4 substrate. The antenna was initially simulated using HFSS software, and to validate the accuracy of the results, it was also analyzed with CST Microwave Studio. Moreover, a prototype was constructed for experimental testing, with measured results showing strong agreement with the simulations. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a compact metasurface antenna with reconfigurable radiation patterns designed for 5G mm‐wave applications. The antenna consists of a metasurface with 3 × 3 unit cells of modified patches, two coupling slots on the ground plane, and a reconfigurable feeding network. The method of characteristic mode analysis is initially employed to identify the modes of the metasurface layer which are responsible for steering the radiation pattern of the antenna at angles of 0° and ±30°. By analysing the surface currents of these modes, the locations of the coupling slots are determined, making it easier to excite and combine the desired modes and steer the main beam of the antenna in specific directions. The pattern reconfigurability is achieved by switching PIN diodes in the microstrip feed network to excite the appropriate coupling slots. The proposed metasurface antenna, with dimensions of 0.9λ0 × 0.9λ0 × 0.08λ0 (where λ0 is the free space wavelength at the centre frequency of 27 GHz), was fabricated and tested. The experimental results showed a wide bandwidth of 22.71% achieved by combining the resonance frequencies of the slots and metasurface layer. Furthermore, the antenna exhibits three distinct main beams at +30°, 0°, and −30° with a peak gain of 8.95 dB.

Abstract This paper presents a novel millimetre‐wave (mmWave) 2D wide‐angle scanning (WAS) phased array antenna (PAA) based on decoupling surface (DS). The proposed element is a coaxial feeding stacked patch antenna structure that consists of an L‐shape coaxial probe, substrate integrated waveguide cavity, slot layer, radiating patch, DS and defective ground structure. The simulated impedance bandwidth for the element is 14.85% (26.18–30.34 GHz). The simulated result of the 2 × 2 array shows that the designed antenna based on DS achieves an isolation of ≥19 dB within the bandwidth. To validate the scanning capabilities of the proposed antenna, an 8 × 8 PAA prototype is fabricated and measured. The measured scanning range of the prototype achieves a 2D WAS range of ±56° at 27 GHz. The proposed antenna shows great potential in application scenarios, such as automotive radar and satellite communication due to its compact design and ability to achieve WAS in two dimensions.

A simple design of a dual linear polarized compact folded loop based feed antenna, operating from 1 to 15 GHz, is presented. The design of a new wide-band twin-lead line to microstrip line Balun required for broadband matching is also explained. The dimensions of the feed are 220 mm × 220 mm × 60 mm. The proposed feed antenna is developed in-house and characterized in an antenna measurement facility at an anechoic chamber. The measured gain of the feed antenna is 8.0 ± 2 dBi from 1 to 9 GHz and 6.0 ± 2 dBi from 10 to 15 GHz. 10 dB beam-width is ±55°, which is nearly constant from 1 to 15 GHz frequency range and makes it suitable for reflector illumination with high aperture efficiency. Port isolation of the feed is better than 20 dB and cross-polarization is better than 15 dB over the band. Simulated and measured gain, cross-polarization, and S-parameters of dual-polarized feed are presented and compared. Based on the secondary pattern analysis from the measured feed pattern, the developed feed is suitable for parabolic reflector antennas operating in the 1–15 GHz frequency range. [ABSTRACT FROM AUTHOR]

This paper presents a compact, broadband, high‐gain dielectric rod antenna. By utilising an air–dielectric hybrid method for designing the radiating and matching sections, gradual variations in the average equivalent permittivity along the rod are achieved, and the mechanism of the method is analysed. This approach facilitates a smooth impedance transition from the feed to the air, resulting in good impedance matching characteristics. Additionally, the antenna is fed through a tapered double‐ridged waveguide (DRW) with a coaxial line to tapered DRW transition. The proposed antenna achieves an impressive impedance bandwidth of 90.2%, covering the entire K and Ka bands. The unique structure of the proposed dielectric rod significantly enhances the antenna's gain, reaching a maximum value of 17.86 dBi. With its small aperture and compact longitudinal dimensions, this antenna is suitable for applications in settings like the Space Environment Simulation Research Infrastructure (SESRI). [ABSTRACT FROM AUTHOR]

This paper presents a high-performance circularly polarized (CP) magneto-electric (ME) dipole antenna optimized for wideband millimeter-wave (mm-wave) frequencies, specifically targeting advancements in 5G and 6G technologies. The CP antenna is excited through a transverse slot in a printed ridge gap waveguide (PRGW), which operates in a quasi-transverse electromagnetic (Q-TEM) mode. Fabricated on Rogers RT 3003 substrate, selected for its low-loss and cost-effective properties at high frequencies, the design significantly enhances both impedance and axial ratio (AR) bandwidths. The antenna achieves an impressive impedance bandwidth of 31% (25.24–34.50 GHz) and an AR bandwidth of 24.9% (26.40–33.91 GHz), with a peak gain of up to 8.4 dBic, demonstrating a high cross-polarization level. The experimental results validate the high-performance characteristics of the antenna, making it a robust candidate for next-generation wireless communication systems requiring CP capabilities. [ABSTRACT FROM AUTHOR]

In short-range microwave imaging, the collection of data in real environments for the purpose of developing techniques for target detection is very cumbersome. Simultaneously, to develop effective and efficient AI/ML-based techniques for target detection, a sufficiently large dataset is required. Therefore, to complement labor-intensive and tedious experimental data collected in a real cluttered environment, synthetic data generation via cost-efficient electromagnetic wave propagation simulations is explored in this article. To obtain realistic synthetic data, a 3-D model of an antenna, instead of a point source, is used to include the coupling effects between the antenna and the environment. A novel printed scalable ultra-wide band (UWB) log-periodic antenna with a tapered feed line is designed and incorporated in simulation models. The proposed antenna has a highly directional radiation pattern with considerable high gain (more than 6 dBi) on the entire bandwidth. Synthetic data are generated for two different applications, namely through-the-wall imaging (TWI) and through-the-foliage imaging (TFI). After the generation of synthetic data, clutter removal techniques are also explored, and results are analyzed in different scenarios. Post-analysis shows evidence that the proposed UWB log-periodic antenna-based synthetic imagery is suitable for use as an alternative dataset for TWI and TFI application development, especially in training machine learning models. [ABSTRACT FROM AUTHOR]

Summary: In this work, an offset microstrip line coupled bilateral rectangular‐shaped dielectric resonator antenna (RDRA) is designed for broadband circular polarization (CP), which is fabricated and experimentally verified. The vertical microstrip is added in an offset position to generate orthogonal modes and the fundamental modes TEx111 and TEy111. The generation of orthogonal modes designates the antenna structure as a CP antenna with orthogonal modes. Moreover, the location of the microstrip feed arrangement is used to control the polarization state in the proposed work. In the proposed design, the simulated and hand‐measured input impedance bandwidth(|S11| ≤ −10 dB) obtained is 32.6% (3.53–4.9 GHz) and 33.2% (3.56–4.98 GHz), respectively, whereas the simulated and measured axial ratio (AR ≤ 3 dB) shows 16.1% (3.71–4.36 GHz) and 17.03% (3.7–4.39 GHz) of axial ratio bandwidth, respectively. This design shows a consistent radiation pattern and good average gain, with acceptable agreement between simulation and hand‐measured results. The simulated result shows 94% radiation efficiency in the working frequency range. [ABSTRACT FROM AUTHOR]

This paper presents a compact metasurface antenna with reconfigurable radiation patterns designed for 5G mm‐wave applications. The antenna consists of a metasurface with 3 × 3 unit cells of modified patches, two coupling slots on the ground plane, and a reconfigurable feeding network. The method of characteristic mode analysis is initially employed to identify the modes of the metasurface layer which are responsible for steering the radiation pattern of the antenna at angles of 0° and ±30°. By analysing the surface currents of these modes, the locations of the coupling slots are determined, making it easier to excite and combine the desired modes and steer the main beam of the antenna in specific directions. The pattern reconfigurability is achieved by switching PIN diodes in the microstrip feed network to excite the appropriate coupling slots. The proposed metasurface antenna, with dimensions of 0.9λ0 × 0.9λ0 × 0.08λ0 (where λ0 is the free space wavelength at the centre frequency of 27 GHz), was fabricated and tested. The experimental results showed a wide bandwidth of 22.71% achieved by combining the resonance frequencies of the slots and metasurface layer. Furthermore, the antenna exhibits three distinct main beams at +30°, 0°, and −30° with a peak gain of 8.95 dB. [ABSTRACT FROM AUTHOR]

A circular ring structure monopolar printed antenna for Doppler and automotive radar systems (24 GHz) is designed with a size of 1.4λ0 × 1.4λ0 × 0.095λ0 mm3 observing |S11|> −20 dB, B.W. of 1.8 GHz and a peak gain of 5.1 dBi. This antenna upgraded initially into 2 × 1 and finally 4 × 1 array, having resonant frequencies at 24 GHz and 28 GHz, respectively. A peak gain of 7.12 and 7.16 dBi through 2 × 1 and 9 and 8.65 dBi through 4 × 1 array is observed at respective operating frequencies. Finally, the 4 × 1 array antenna with the tapered feed of size 4.4λ0 × 2.2λ0 × 0.095λ0 mm3 having |S11|≤ 40 dB at ISM-III (24 GHz) and |S11|≤ −30 dB at 5G (28 GHz) with B.W. of 0.77 GHz and 5.1 GHz, respectively, is proposed, qualifying the obtained measured results. Isolation between each antenna element for the 4 × 1 array is ≤ −20 dB with a maximum value of −65 dB. The ECC observed between antenna elements is less than 0.045 and DG is 10. An equivalent circuit is also evaluated for the proposed antenna. The quantification results present that the developed array antenna has excellent performance over the dual band. [ABSTRACT FROM AUTHOR]

This study investigates the use of spoof surface plasmon polaritons (SSPPs) as an effective feeding mechanism for antennas functioning within the extremely high-frequency (EHF) range. A novel method is proposed for feeding a dielectric rod antenna with SSPPs, featuring a simple design made from FR-4 material with a relative permittivity of 4.3. In contrast to traditional tapered dielectric rod antennas and their feeding configurations, this design shows promise for achieving a gain of up to 16.85 dBi with an antenna length of 7.6 λ0. By carefully optimizing the design, impedance matching and directional radiation characteristics were obtained at 7.3 GHz. Simulations were conducted using CST Microwave Studio to validate and evaluate the design's performance. The enhanced gain, improved impedance bandwidth, and use of cost-effective materials such as FR-4 present a compelling case for adopting this design in future wireless communication technologies. Additionally, the remote sensing properties of the feeder can be utilized for concealed object detection, material characterization, and the analysis of the spectral properties of materials. [ABSTRACT FROM AUTHOR]

The rise of CubeSats has unlocked opportunities for cutting-edge space missions with reduced costs and accelerated development timelines. CubeSats necessitate a high-gain antenna that can fit within a tightly confined space. This paper is primarily concerned with designing a compact Ku-band offset cylindrical reflector antenna for a CubeSat-based Earth Observation mission, with the goal of monitoring Arctic snow and sea ice. The development of a Ku-band offset cylindrical reflector, with a compact aperture of 110 × 149 mm2 (6.3λ × 8.5λ), is described alongside a patch array feed consisting of 2 × 8 elements. The patch array feed is designed using a lightweight Rogers substrate and is utilized to test the reflector. Adopting an offset configuration helped prevent gain loss due to feed blockage. Analyzing the reflector antenna, including the feed, thorough simulations and measurements indicates that achieving a gain of 25 dBi and an aperture efficiency of 52% at 17.2 GHz is attainable. The reflector's cylindrical shape and compact size facilitate the design of a simple mechanism for reflector deployment, enabling the antenna to be stored within 1U. The array feed and reflector antenna have been fabricated and tested, demonstrating good consistency between the simulation and measurement outcomes. [ABSTRACT FROM AUTHOR]

A compact highly selective broadband filter antenna with an asymmetric feed structure is proposed. The radiating patch of the antenna unit consists of a central elliptical patch and a pair of semi‐annular patches, and the antenna forms multiple coupling paths from the feed ports to the radiating patches to generate a radiation null (6.28 GHz), which achieves the roll‐off rate of 193 dB/GHz. The innovation of this design is that asymmetric L‐shaped branches of about half a wavelength are added on both sides of the microstrip feedline of the antenna to expand the operating bandwidth and generate a low‐frequency radiation null (4.66 GHz), which achieves the roll‐off rates of 164 dB/GHz. The simulated results show that impedance bandwidth is 23.8% (4.77–6.06 GHz) with the peak gain of 5.86 dBi, which size is 0.5λ0 × 0.5λ0 × 0.09λ0. Then, a 2 × 2 filtered antenna array is designed for experimental validation. The test results indicate that the impedance bandwidth of the antenna array is 21.5% (4.45–5.52 GHz), the in‐band gain is greater than 10 dBi and flat, and the out‐of‐band rejection level is greater than 20 dB. Attributed to the characteristics of easy and inexpensive manufacturing, the designed antenna has well application prospects in modern wireless communication systems. [ABSTRACT FROM AUTHOR]

This letter proposes a compact air‐substrate single conductor endfire antenna, characterized by stable endfire radiation, high gain, high gain‐to‐length ratio and easy assembly. The proposed antenna is fed by air‐substrate double‐sided parallel strip lines (DSPSLs) in the TEM mode, ensuring stable endfire radiation pattern. Evolved from the periodic leaky‐wave antenna design, it also achieves high gain. Moreever, the radiating elements can couple energy through two paths, achieving an almost uniform electric field distribution, which contributes to a high gain‐to‐length ratio. Notably, a single‐conductor structure is achieved by terminating the short‐circuited DSPSLs, which simplifies the assembly process and minimizes manufacturing complexity. Finally, the proposed compact single‐conductor antenna is simulated, fabricated, and measured. The proposed endfire antenna features a compact size of 1.90λ0 × 0.42λ0 × 0.05λ0 operating at the center frequency of 5.00 GHz, where λ0 denotes the free‐space wavelength. According to the measurement results, the antenna also achieves a high gain of 11.37 dBi and a high gain‐to‐length ratio of 7.21, exhibiting a wide 1‐dB gain bandwidth of 4.00–5.30 GHz. These features make the antenna well‐suited for diverse long‐distance communication applications. [ABSTRACT FROM AUTHOR]

A terahertz (THz) wave generator for multiplying the output power from arrayed photomixers is developed. The generator is composed of two uni-traveling carrier photodiodes (UTC-PDs) as the photomixers, a 2 × 1 T-junction power combiner and a microstrip rectangular patch antenna on a silicon carbide (SiC) substrate in which photocurrents of 300 GHz from the UTC-PDs are combined to be fed to the antenna. Experimental results show that the output power is multiplied by 5.8 dB (approximately fourfold) compared to that of a single UTC-PD. This advancement has the potential for further multiplication of THz power by cascaded combining of a larger number of UTC-PDs. [ABSTRACT FROM AUTHOR]

Due to the recent expansion in the generations of the communications systems, it is utmost priority to transmit a large amount of data over a wideband frequency spectrum. For this single ultra-wideband (UWB) antennas are the prime choice as compared to the multiple narrow band antennas. A modified pentagonal fractal patch antenna with a modified ground plane covering ultra-wideband has been proposed. The antenna has a compact size of 25 mm × 25 mm × 1.6 mm with peak gain of 2.2 dB. The UWB coverage of the design is achieved by implementing modified co-planar ground, modified fractal geometry and coplanar feed. The proposed design possesses the significant resonance and radiation performance with very compact size on low-cost substrate while covering the whole UWB. Finally, the simulated resonating and radiation characteristics have been validated with the measured characteristics of the fabricated prototype and the results are quite promising. [ABSTRACT FROM AUTHOR]

This research proposition introduces a novel microstrip antenna design that features triple notches for ultra-wideband (UWB) applications. The antenna, measuring 35.4 mm × 28.82 mm × 1.57 mm, incorporates rectangular and semi-circular slots, as well as a pentagonal stub. A modified U-shaped slot on the pentagonal stub creates one notched frequency band at 3.3–3.7 GHz. Additionally, two Split Ring Resonators (SRRs) are integrated into the antenna's rear surface, resulting in two more notched bands at 5.1–5.8 GHz and 7.1–7.8 GHz. Operating within a frequency range from 3 to 11.2 GHz with VSWR ≤ 2, the antenna effectively excludes the triple stop bands at 3.3–3.7 GHz (11.4%), 5.1–5.8 GHz (12.8%) and 7.1–7.8 GHz (9.4%). The proposed antenna has been successfully prototyped and verified. An extensive result analysis has been conducted, confirming that the developed antenna is suitable for application in a range of wireless systems. Moreover, the article includes the implementation of an equivalent circuit for the proposed antenna. [ABSTRACT FROM AUTHOR]

Radio power transmission is studied herein. A rectenna with high‐efficiency microwave power transmission is proposed. Improvement on the traditional Yagi antenna structure is implemented by using a rectenna. In this design, the antenna is fed by a coplanar waveguide, and the impedance bandwidth is widened by adding a set of radiation dipoles. A set of parasitic directors is used to enhance the directionality of the antenna. A rectifier circuit based on a power‐recovery network is designed using an open branch‐line network with harmonic rejection characteristics as a low‐pass filter. The rectifier network topology is adopted with a diode in parallel connection to increase the output voltage of the circuit. The reflected power generated by the impedance mismatch can be recycled by the power‐recovery network. Thus, the rectifying efficiency can be improved. Finally, experimental data show that the radiofrequency–direct current power conversion efficiency of the rectenna can be as high as 77.5% at the operating frequency 2.45 GHz and the input power 12 dBm. The proposed rectenna can be potentially used for the power supply of various wireless sensor nodes with high efficiency. [ABSTRACT FROM AUTHOR]

In this paper, a design and radiation characteristics of an electrodynamics model of a capacitive feed printed dipole array element are presented. The array element is for operation in a millimeter wave range (25-26 GHz) of the fifth-generation communication systems for the wireless local network. It has a linear polarization. On the level of the VSWR less than 3, its operating frequency band is in the range from 23.325 to 28.201 GHz. In the needed frequency range, the value of the VSWR is no more than 1.3. Based on this array element was made the antenna array model with size 4 × 4. On the level of the VSWR less than 3, its operating frequency band is less than array elements and is located in the range from 23.778 to 27.865 GHz. In the needed frequency range, the value of the VSWR of its corner elements is no more than 1.6 and no more than 1.5 for all other elements. The value of the realized gain is in the range from 16.8 to 17.1 dB. [ABSTRACT FROM AUTHOR]

Reconfigurable intelligent surface (RIS) is anticipated to augment the performance of beyond fifth-generation (B5G) and sixth-generation (6G) networks by intelligently manipulating the state of its components. Rather than employing reflective RIS for aided communications, this paper proposes an innovative transmissive RIS-enabled transceiver (TRTC) architecture that can accomplish the functions of traditional multi-antenna systems in a cost-effective and energy-efficient manner. First, the proposed network architecture and its corresponding transmission scheme are elaborated from the perspectives of downlink (DL) and uplink (UL) transmissions. Then, we illustrate several significant advantages and differences of TRTC compared to other multiantenna systems. Furthermore, the downlink modulation and extraction principle based on time-modulation array (TMA) is introduced in detail to tackle the multi-stream communications. Moreover, a near-far field channel model appropriate for this architecture is proposed. Based on the channel model, we summarize some state-of-the-art channel estimation schemes, and the channel estimation scheme of TRTC is also provided. Considering the optimization for DL and UL communications, we present numerical simulations that confirm the superiority of the proposed optimization algorithm. Lastly, numerous prospective research avenues for TRTC systems are delineated to inspire further exploration. [ABSTRACT FROM AUTHOR]

This research endeavor sought to explore a small (12 x 12 x 0.8) mm³ microstrip patch antenna. This design boosts the characteristic of microwave circuits, such as narrow bandwidth, gain, reduced return loss, VSWR, also enhance the current distribution, etc. The proposed antenna is built on a Rogers RT Duroid 5880 board of 0.8 mm in thickness and exhibits a dielectric constant of (ɛr = 2.2). It is intended to work in the frequency range of 28 GHz to 32.5 GHz. To improve the radiation performance of the suggested antenna structure, rectangular slots with inset feed technique have been created from the radiating patch for the change of current distribution. The proposed antenna has a 4 GHz bandwidth and operating frequency range is 28 GHz to 32.5 GHz. Because of this, the suggested antenna design is compact and suitable for greater frequency ranges. The simulation outcomes demonstrate that the antenna model is accurate. Performance measurements like return loss, gain, and VSWR have improved. All necessary simulations are carried out using the EM simulator Ansys HFSS, and a comprehensive comparative study based on the present antennas is accomplished. The suggested antenna achieves high gain for the desired frequency band, has a VSWR of less than two, and has good impedance matching at |S11| < - 10 dB. The recommended antenna can be used for 5G high-frequency applications because it resonates at millimeter wave frequencies. These outstanding outcomes indicate that the suggested antenna would be a respectable option for 5G mm-wave applications. [ABSTRACT FROM AUTHOR]

In this paper, a definition for the active differential reflection coefficient of the differentially-fed antenna array is proposed. Each antenna is fed by the differential port with the equal-amplitude anti-phase signal input. According to the active reflection coefficient of the conventional single-ended antenna array, the active differential reflection coefficient definition of the differential antenna array is given and analyzed. It is derived that the active differential reflection coefficient of the differential port m is half of the active reflection coefficient sum for the single-ended port m+ and m−. In addition, the active differential impedance expression is also given. To verify the active differential reflection coefficient, a differential three-element microstrip patch antenna array was designed, fabricated, and measured. The experimental results validate the proposed theoretical analysis. This work will provide a new insight into the differential antenna array. [ABSTRACT FROM AUTHOR]

A differentially fed shorted triangular patch antenna with high cross-polar discrimination (XPD) and pattern symmetry about the boresight is presented. A new shorted triangular patch configuration is projected that uses a shorting wall at the middle apart from the widely explored back short. Two dedicated L-probes have been conceived for the excitation of the antenna in the TM11 and TM20 modes. The differentially fed antenna exhibits 49.43% impedance bandwidth and produces XPD ≈ 43 dB without any pattern tilt and 9 dBi gain. The achieved high XPD, patterns without tilt, and wider bandwidth are the superiority of the proposed antenna compared to earlier reports. An X-band prototype has been realized and experimentally validated. Relevant experimental results are also presented. [ABSTRACT FROM AUTHOR]

This study presents a substrate integrated waveguide (SIW) broadband circularly polarized (CP) high‐gain low‐profile magneto‐electric dipole antenna array. The antenna array is characterized by wide impedance bandwidth (IBW), novel CP operating principle, small form factor, and good radiation performance. First, the antenna element consists of a two‐layer dielectric substrate, two pairs of magneto‐electric dipoles, and a SIW cavity coupled and fed through a cross‐shaped rectangular slit. To achieve a wide CP bandwidth (BW), a pair of magneto‐electric dipoles is rectangularly chamfered and then an "L" type parasitic patch is introduced. The simulation results show that the antenna element has an axial ratio (AR) BW of 14.2% in the 31.48–36.16 GHz range, the IBW in the 29.08–35.98 GHz range is 21.2%, and the gain is greater than 8 dBic in all bands. The antenna exhibits stable patterns and wide overlap IBW (31.48–35.98 GHz). Then, a planar 2 × 2 antenna array fed by a one‐part‐four SIW power divider was designed, fabricated, and measured. The measured results show that the array has an ARBW of 14% in the range of 31.29−35.83 GHz, an IBW of 21.8% in the range of 29.28–35.83 GHz, and a peak gain of 14.1 dBic. [ABSTRACT FROM AUTHOR]

A miniaturized asymmetric coplanar strip fed with meander lines is developed for hexaband wireless applications. Multiband with compact size of the antenna is developed by using meander lines. The designed antenna is enhanced by an increased number of meander lines. The invented antenna is composed of three meander lines, it yields the antenna to excite 1.13, 2.35, 2.91, 3.46, 3.96, and 4.5 GHz, respectively. The prototype antenna is fed by ACS, which is printed on a 14 × $\times $ 24 × $\times $ 1.6 mm3 FR‐4 substrate and dielectric constant of Ɛr = 4.4. MATLAB tool is utilized in the ANN computation to amend the physical values of the antenna. The calibrated and simulated radiation attributes are identical with each other. The designed antenna provides distinguishing characteristics such as good reflection coefficient, impedance matching, and size miniaturization. It imparts empirical peak gains of 0.028 dBi at 1.14 GHz, 1.305 dBi at 2.35 GHz, 1.54 dBi at 2.86 GHz, 1.79 dBi at 3.43 GHz, 2.43 dBi at 3.96 GHz, and 2.58 dBi at 4.5 GHz, which is suitable for GSM/WLAN/WiMAX and C‐band wireless applications. [ABSTRACT FROM AUTHOR]

In this paper, a novel stacked wideband differentially feed antenna with dual polarizations is designed for base station. The circular parasitic patch deepens the resonance depth by slotting. Two linear dipoles are placed at ±45 - under the circular parasitic patch to reduce the overall size of the antenna. The antenna introduces a cross-shaped differential feed to achieve high port isolation. Finally, the designed antenna is fabricated and tested. The test results show that the differential reflection coefficient |Sdd11| is more than 15 dB. The antenna achieves a differential impedance bandwidth of 53.1% (1.63 GHz-2.8 GHz). The isolation is greater than 42 dB over the entire operating bandwidth. The antenna also has a stable gain of 8.2 ± 0.4 dBi and a half-power beamwidth of 65° ± 4°. [ABSTRACT FROM AUTHOR]

This paper presents a novel millimetre‐wave (mmWave) 2D wide‐angle scanning (WAS) phased array antenna (PAA) based on decoupling surface (DS). The proposed element is a coaxial feeding stacked patch antenna structure that consists of an L‐shape coaxial probe, substrate integrated waveguide cavity, slot layer, radiating patch, DS and defective ground structure. The simulated impedance bandwidth for the element is 14.85% (26.18–30.34 GHz). The simulated result of the 2 × 2 array shows that the designed antenna based on DS achieves an isolation of ≥19 dB within the bandwidth. To validate the scanning capabilities of the proposed antenna, an 8 × 8 PAA prototype is fabricated and measured. The measured scanning range of the prototype achieves a 2D WAS range of ±56° at 27 GHz. The proposed antenna shows great potential in application scenarios, such as automotive radar and satellite communication due to its compact design and ability to achieve WAS in two dimensions. [ABSTRACT FROM AUTHOR]

[Objective] Topology optimization is an innovative computational technique that determines the optimal material distribution or structural configuration to meet the specific design criteria. This technique is crucial in the intelligent microwave device design due to its high degree of freedom compared with shape or size optimization. Microwave engineering is an important fundamental course for physics, electronic engineering, and communication engineering students. Incorporating device topology optimization experiments into the curriculum can make the abstract concepts in the microwave theory and network theory more easy to comprehend, this not only bridges classroom knowledge with advanced industrial design techniques but also cultivates students' analytical, modeling, and engineering skills. [Methods] Using concrete examples of antenna matching network optimization, the experiment reported in this study explores the method and implementation techniques of topology optimization. The investigated network topology optimization experiment involves two interconnected phases: theoretical modeling and numerical optimization. Initially, this study uses the impedance matrix approach for the accurate and fast modeling of a grid-like antenna matching network. Once the connection relationship in the matching network is determined, a closed-form expression of the network scattering parameters can be obtained explicitly, eliminating the need for computationally expensive full-wave simulations and thus accelerating the forward problem solving during each iteration of topology optimization. Subsequently, a genetic algorithm, which is a type of powerful stochastic optimization algorithm, is leveraged to optimize the connection relationship in the grid-like network, achieving an intelligent on-demand design of the antenna operating frequency band. The genetic algorithm can handle the ill-posed optimization problem using mechanisms such as selection, crossover, and mutation to yield solutions that approximate the optimal solution of the search process. [Results] This study demonstrates the resultant structures and performances of topology-optimized narrow-bandwidth monopole antennas operating at center frequencies of 1.00, 1.20, and 1.40 GHz, as well as a wideband antenna operating in the range of 1.099-1.395 GHz. The narrow-bandwidth design is achieved by introducing a single resonance of the matching-network-loaded antenna that closely matches the prescribed center frequency, while the wideband design emerges from creating two resonances with an appropriate frequency separation. Two important figures of merit--the reflection coefficient and antenna's total efficiency--are introduced in these experiments to assess the antenna performance. These metrics measure the power reflection from the antenna feeding port and the ratio of the radiated power to the incident power, respectively. Following the topology optimization of the grid-like antenna feeding network, the values of the port reflection coefficients of the monopole antennas reduce notably from nearly 0 dB to below -10 dB over the specified frequency band, and the antenna efficiencies are generally higher than 90% over the operating band, with peak efficiency values exceeding 95%. [Conclusions] This study systematically elucidates the theory and workflow of network topology optimization, emphasizing the combined use of impedance matrix modeling and genetic algorithms. Numerical optimization experiments are conducted to obtain an on-demand intelligent design of the antenna matching network. These experiments reveal a substantial improvement in the antenna radiation performance after incorporating the topology-optimized matching network. This experiment serves as a comprehensive and advanced training opportunity for microwave- and antenna-related courses, significantly enhancing undergraduate students' ability to tackle complex engineering problems. [ABSTRACT FROM AUTHOR]

Here, a transition technique for converting signals from rectangular waveguide to coupled microstrip lines (CML) is presented, which provides a solution for differential antenna array feeding of automotive radar. The key to the proposed transition structure is to connect the coupling patches together with a short‐bridge structure, thus forming a quasi‐loop structure. Through the short bridge, the radiation efficiency of the antenna is greatly enhanced, and the mode conversion from TE10 of rectangle waveguide to differential mode of coupled microstrip line is realized effectively under the extremely compact size. Finally, the designed transition structure is manufactured and measured. The experimental results show that the back‐to‐back insertion loss is lower than 0.65 dB and the return loss is higher than 16.8 dB in the W‐band (75–110 GHz), which is the best performance and the simplest design among the relevant transition transitions reported so far. [ABSTRACT FROM AUTHOR]

This paper proposes and analyzes a 2 × 2 multi‐input multioutput antenna based on an open‐loop resonator structure and an inverted L structure. The top layer of the antenna uses symmetric inverted hook‐shaped and inverted L branches and is connected to the bottom layer of the dual‐feed port and the ground plane using the VIAs, respectively. The open‐loop resonator structure at the bottom of the antenna and the top layer of the branched circuit are resonated to provide wide‐bandwidth and dual‐frequency characteristics. The substrate uses FR4 with an area of 40 × 30 × 0.8 mm3. Although the two antenna feed ports are very close to each other, using via to connect the defective bottom ground structure and the top inverted L‐shaped branch, the isolation still achieves an excellent performance of 15 dB. The antenna has multiband application characteristics, and the bands include 2.29–5.51, 6.14–10.26, 2.29–5.33, 5.19–6.64, and 6.78–10.16 GHz. In pattern and MIMO transmission efficiency measurement, the peak radiation efficiency is 89%, the peak gain is 8.5 dBi, and the ECC is less than 0.034. In the transmission efficiency measurement mode using 64‐QAM, watching the error vector magnitude at 2.56 and 5.11 GHz, the demodulation effect is very good, and the respective throughput results are 100% and 79.2%. The broadband characteristics of the antenna have a variety of applications, and it is simulated at the specific absorption rate, which meets the standards set by the Federal Communications Commission and is very suitable for use in wearable devices. The antenna can be applied to the X‐band, n77, n79, Sub‐6 GHz, WiMax, DSRC, WiFi 6, WiFi 6E, WiFi 7, C‐V2X, and C‐band. [ABSTRACT FROM AUTHOR]

In this work, varoius dual-band WLAN MIMO antennas are designed and implemented. Measuremnet Results show that the working bands of these antennas are (2.40–2.48) GHz and (5.1–6.0) GHz. Metallic barrier are used to increase isolation among the ports of the WLAN MIMO antennas. For the two elements WLAN MIMO antenna with parrallel feed, isolation between ports of this antennas is higher than 18 dB. For the 2*2 (four) elements WLAN MIMO antenna with parrallel feed, isolation between ports of this antennas is higher than 19 dB. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper starts with the proposal of an enhanced version of a planar rectangular slot antenna fed by the quasi‐TEM printed ridge gap waveguide (PRGW), attended with a numerical study of a miniaturization procedure showing the limitations of the conventional PRGW‐based antennas. Then innovative solution is introducing a new miniaturized pure TEM wide‐band slot antenna utilizing double PRGW (D‐PRGW) technology; the proposed approach is self‐packaged and shows high potential for enhancing antenna performance, particularly in terms of bandwidth, gain, and compactness. This technology is featured with low loss, high performance, and compact size; it consists of surrounding the ridge area with a double layer of electromagnetic band gap (EBG) lattice instead of one to eliminate the surface waves effectively and keep the signal completely confined inside the ridge area with strict minimum rows of EBG. Therefore, a broad impedance matching bandwidth (|S11| ≤ −10 dB) of 33.33% is obtained from 50 to 70 GHz, which covers the unlicensed NR parts (n262; amp; n263) of the V band. Furthermore, the antenna achieves a peak gain of approximately 16 at 65 GHz while the overall efficiency remains above 90% across the entire operating frequency band. The high performance along with the compact size of this novel design makes it a good candidate for 5G wireless communications applications centered around 60 GHz. [ABSTRACT FROM AUTHOR]

A ground station antenna system features a conical horn attached to a microstrip antenna as an alternate receiving feed antenna. The proposed microstrip antenna has circular polarization and operates in the X-band. The far-field parameters of the antenna are measured after developing and simulating the combination of a conical horn and a microstrip antenna. The modeling results for a microstrip antenna with a conical horn offer a working bandwidth of 930 MHz, spanning frequencies 7.44 GHz to 8.37 GHz. The axial ratio measurements for a microstrip antenna joined with a conical horn produce a working bandwidth of 150 MHz, covering frequencies ranging from 7.72 GHz to 7.87 GHz. The conical horn is attached to a microstrip antenna and has a gain of 15.1 dB. The proposed antenna is designed to meet ground station antenna requirements by pairing it with a parabolic reflector with a diameter of 3.7 meters. The primary focus antenna of the proposed design was chosen. The feed antenna and parabolic reflector should be positioned at a focus point distance of 1110 mm for a total gain of 38.9 dB at 7.8 GHz frequency. The proposed antenna can be applied on X-band remote sensing ground stations as a receiving antenna. [ABSTRACT FROM AUTHOR]

The Spaceborne Global Lightning Location Network (SGLLN) serves the purpose of identifying transient lightning events occurring beneath the ionosphere, playing a significant role in detecting and warning of disaster weather events. To ensure the effective functioning of the wideband electromagnetic pulse detector, which is a crucial component of the SGLLN, it must be tested and verified with specific signals. However, the inherent randomness and unpredictability of lightning occurrences pose challenges to this requirement. Consequently, a high-power electromagnetic pulse radiation system with a 20 m aperture reflector is designed. This system is capable of emitting nanosecond electromagnetic pulse signals under pre-set spatial and temporal conditions, providing a controlled environment for assessing the detection capabilities of SGLLN. In the design phase, an exponentially TEM feed antenna has been designed firstly based on the principle of high-gain radiation. The feed antenna adopts a pulser-integrated design to mitigate insulation risks, and it is equipped with an asymmetric protective loading to reduce reflected energy by 85.7%. Moreover, an innovative assessment method for gain loss, based on the principle of Love's equivalence, is proposed to quantify the impact of feed antenna on the radiation field. During the experimental phase, a specialized E-field sensor is used in the far-field experiment at a distance of 400 m. The measurements indicate that at this distance, the signal has a peak field strength of 2.2 kV/m, a rise time of 1.9 ns, and a pulse half-width of 2.5 ns. Additionally, the beamwidth in the time domain is less than 10°. At an altitude of 500 km, the spaceborne detector records a signal with a peak field strength of approximately 10 mV/m. Particularly, this signal transformed into a nonlinear frequency-modulated signal in the microsecond range across its frequency spectrum, which is consistent with the law of radio wave propagation in the ionosphere. This study offers a stable and robust radiation source for verifying spaceborne detectors and establishes an empirical foundation for investigating the impact of the ionosphere on signal propagation characteristics. [ABSTRACT FROM AUTHOR]