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This paper focuses on designing a new structure of beamforming networks with an array antenna to control the beams. The 3×4 array antenna structure connects to the 3×3 Rotman lens beamformers to achieve this goal. The middle time delay line is around 14 mm. The design allows the x-axis to cover +25, 0, −25 degrees. Therefore, this work targets fifth generation (5G) application, which necessitates coverage in all directions by other base stations or users. Computer Simulation Technology (CST) microwave software facilitates the simulation process. The design begins with a single microstrip patch antenna, designed to function as an array antenna resonating at 26 GHz. The half-lambda separation (λ/2) among antennas gives 13.8 dBi gain with S11< −10 dB. The final structure for beamforming networks has a gain of 14 dBi. This work uses the Roger 5880 substrate, which has a dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 0.127 mm. [ABSTRACT FROM AUTHOR]

A novel Fabry-Perot cavity (FPC) antenna with metasurface is presented, which can achieve broad bandwidth and low profile. Traditional FPC antennas, with rectangular microstrip antennas as feeds, have limited impedance bandwidth and struggle to make a compromise in the gain bandwidth and maximum gain value. To obtain wide bandwidth, the FPC antenna proposed in this paper utilizes a feed antenna loaded with parasitic patches. To widen impedance bandwidth and gain bandwidth and reduce the profile, a positive phase gradient partially reflective surface (PRS) and an artificial magnetic conductor (AMC) are located above and below the feed antenna, respectively. The phase property of the PRS and AMC also brings in a more smooth gain value curve. To further increase gain values, four metal reflector plates are located around the proposed antenna. The overall dimension of the antenna is 2.5λ0×2.5λ0×0.25λ0 (λ0 is the free space wavelength at 7.5 GHz). Simulated results show that the resonant cavity antenna proposed in this letter exhibits an impedance bandwidth of 13.3% (7-8 GHz) and a 3 dB gain bandwidth of 14.3% (7.02-8.10 GHz). The maximum gain in the whole operating band is 14.5 dBi. The measured results are in good agreement with the simulated ones. [ABSTRACT FROM AUTHOR]

This paper presents an ultrawideband dual circularly polarized (CP) rectenna for wireless energy harvesting (WEH) applications. It is mainly composed of a dual CP antenna and an ultrawideband rectifier. The receiving antenna is fed by a coplanar waveguide (CPW) and it has two input ports. The proposed ultrawideband rectifier has a two-cascaded voltage doubler configuration. This configuration means the proposed rectifier's input impedance has less sensitivity to frequency variation. Thus, a wide bandwidth can be achieved. For validation, a prototype is designed, fabricated and measured. The measured results show that the axial ratio (AR) bandwidth of the proposed rectenna is from 1.35 to 3.10 GHz (for AR <3 dB). In this frequency range, the rectenna's power conversion efficiency (PCE) is higher than 55%. These results indicate that the proposed rectenna is highly efficient and suitable for wideband high-efficiency WEH systems. [ABSTRACT FROM AUTHOR]

A dual-polarized broadband coupled feed dipole antenna loaded with artificial magnetic conductor (AMC) structure is proposed. The proposed AMC structure with 4x4 elements shown in this paper consists of four perfect electrical conductor (PEC) rectangular strips and a ring to reduce the profile height of the dual-polarized dipole antenna. In addition, the dual-polarization antenna adopts coupling feed microstrip to excite two pairs of bow-tie patch. The overall size of the coupling feed dipole antenna is 1.1λ0x1.1λ0x0.09λ0 at 5.5 GHz. Measured results shows that the proposed dual-polarization antenna loaded AMC exhibit a 25.2% common working bandwidth (4.75-6.12 GHz). The isolation is less than -14 dB, and the peak gain is 10.6 dBi. This dipole antenna with AMC structure has the virtues of low profile, wide band, and good radiation performance and it has the potential to be used in C-band communication. [ABSTRACT FROM AUTHOR]

A compact WLAN band-notched reconfigurable wideband antenna using two mushroom-like electromagnetic band-gap (EBG) structures is proposed in this paper. It is designed based on a dual wideband microstrip feed patch antenna with operating frequency bands of 2.2-3.7 GHz and 4.8-6 GHz. One of the EBG cells is positioned alongside the feed line, while the other EBG cell is laid on the back of the substrate. The patch or ground of the two EBG units are fed with a stronger current through a ground slot and a parasitic stub respectively, and the connections between the EBG structures and the antenna are controlled by loading a PIN diode with two 56 pF DC blocking capacitors. The advantage of this proposed design is that the antenna and the EBG unit can be designed independently. The proposed antenna has an overall size of 35×46×1.6 mm3. When testing the S11 of the antenna, the influence of the bias circuit on the antenna is also considered. The measured results show that the proposed antenna can generate two notched bands of 2.3-2.49 GHz and 5.11-5.51 GHz of WLAN, and the realized gain in the notch bands can be reduced to -2.65 dBi and -4.55 dBi, respectively, demonstrating its anti-interference characteristics, and can be applied in band notch broadband communication systems or anti-interference communication equipments such as unmanned aerial vehicles and radars. [ABSTRACT FROM AUTHOR]

This paper introduces a localized masked thermal therapy method for only the breast through the Fresnel region. A pyramidal horn antenna has been used as a hyperthermia system applicator. The antenna is fed by a Yagi array and resonates at 4.74 GHz. A metal plate with a square slot masked the breast phantom. The antenna irradiates the breast phantom for 5 and 10 minutes with input power of 10 and 20 watts (W). Thermal and specific absorption rate (SAR) distributions are studied under the same conditions for a fair comparison between masked and unmasked system performance. The square slot dimensions are altered, and their effects are studied considering the phantom heated area. Moving from unmasked to masked hyperthermia scenarios, a heated area size reduction of 99.87 % is achieved along with a very considerable SAR value reduction. The masked scenario elevates the breast temperature to 43 °C in a very concentrated area. The proposed system can elevate only an area of 2×2 mm2 of the breast tissue to a temperature of 40 °C in 5 minutes, and that is a very promising result in hyperthermia therapy applications. [ABSTRACT FROM AUTHOR]

A three-dimensional compact propellershaped circularly polarized ceiling-mounted antenna loaded by inverted L-shaped slot is proposed in this paper. This three-dimensional structure has a small size, single feed and half-plane radiation mode. The antenna is composed of four alternately welded radiating elements and a disc reflector. Each radiating element is formed by etching a rectangular microstrip radiating patch and a trapezoidal microstrip radiating patch on the surface of the substrate. The four radiating elements are welded vertically on the disc reflector. The back of the disc reflector has the ground plane. The antenna is fed coaxially through the via in the center of the disc reflector. The result demonstrates that the 10-dB impedance fractional bandwidth achieves 66.3% (4.4-8.94 GHz). The 3-dB axial ratio fractional bandwidth is 2.2% (6.44-6.58 GHz). The radiation characteristic is close to halfspace radiation on the xoz plane and the yoz plane. The peak gain of the antenna is 3.22 dBi. The simulation and measurement results are in good agreement. With its compact structure, effective coverage, miniaturization, etc., the antenna is very suitable for applications such as biomedical monitoring equipment and short-range radio communications. [ABSTRACT FROM AUTHOR]

A new antenna array system is introduced which enables the movement of a near-field focused beam by change of frequency. The shift in the beam is achieved by using multi-wavelength transmission lines between successive elements of the array. At the designed frequency the beam is focused at the focal point. Due to the differences in the transmission line lengths feeding the antenna elements, a progressive phase change occurs between these elements. These phase differences between the elements cause a shift in the beam position. An 8×8 patch antenna array system was designed at 2.4 GHz on a microstrip to implement the proposed system. Two substrates were used: one for the patch antenna array and the other one for the feed network and transmission lines. A full-wave simulation model was used to analyze this design and demonstrate the movement of the beam. For this design, the focused beam is moved 310 mm by changing the frequency from 2.2025 GHz to 2.5750 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a novel low-profile wideband planar inverted-F antenna (PIFA) with co-design of the ground plane for WLAN applications and IoV applications is proposed. This antenna consists of three parts: a slotted radiating patch, a vertical shorting plate and a ground plane with a cross-shaped slot. The influence and the parameter of the slot are discussed. The antenna is fed by a 50 Ω coaxial line and a shorting pin is also used in this design. The overall size of the antenna is 30×44×3.5 mm3. The whole structure is simulated in ANSYS Electronics Desktop 2018.0 and several prototypes are made to verify the simulation results. The bandwidth of the antenna can reach 3.96 GHz (-10 dB) and cover the frequency range of 5.64-9.6 GHz. The max gain of the antenna is 5.4 dBi. [ABSTRACT FROM AUTHOR]

A printed dual-band antenna is designed to resonate at 3.5 GHz with the measured gain of 6.38 dBi and at 5.5 GHz with that of 5.84 dBi for the WiMAX application. The bandwidth of this antenna at 3.5 GHz and 5.5 GHz is 8% and 5%, respectively. The radiation efficiency of 91.45% is obtained at 3.5 GHz and that of 89.56% at 5.5 GHz. A novel approach based on the perturbation technique is used to relate the resonant frequency to the electromagnetic energy stored and the volume of the proposed antenna's structure. The dual resonant length of this antenna is determined by a parameter named as the length reduction factor, which is computed by the curve fitting method. A polynomial equation connects the length reduction factor and resonance frequency. The resonant cavity model has been used to derive the resonant frequency equations for dual bands. The simulation and measured results are used to validate the analytically predicted resonant frequency caused by the structure perturbation and cavity technique and show good agreement. This antenna is fed by a balanced parallel plane, which conveniently facilitates the PCB's integration. [ABSTRACT FROM AUTHOR]

In this paper, a microstrip patch antenna fed by a waveguide using an end-wall iris through ground plane has been modelled. The iris feed technique was proposed to overcome the narrow bandwidth problem of microstrip patch antenna. The iris is sized so that it is resonant and subsequently the antenna operates under the fusion of two modes relating to the iris and the patch, resulting in a wideband radiation characteristic with dual resonance. Measurement demonstrates the single bandwidth dual resonance type and the radiation bandwidth of (8 GHz-10.6 GHz). In order to show the impact of the iris feed technique on microstrip patch antenna's bandwidth, a comparison with some state-of-the-art works proposing various bandwidth enhancement techniques in the X-band is made. The proposed prototype, with a size of 1.76λ0×1.65λ0×1.29λ0, is more compact than several designs. It has a fractional bandwidth of 27.9%, thus it presents the prototype with the widest bandwidth with the simplest design fabrication. With regard to the electromagnetic modelling, this work is oriented towards the use of the hybrid MOM-GEC method in order to be able to perform a rigorous electromagnetic. It has been found that the MOM-GEC model is more efficient in terms of memory requirements and approximately four times faster than HFSS simulator software. [ABSTRACT FROM AUTHOR]

A novel 'T' square wideband fractal antenna is proposed for satellite communication. The Wideband is achieved through the 'T' square fractal design and CPW feed. At first, a conventional square-shaped patch antenna is designed. Then the square-shaped patch is replaced by a Type-I fractal to achieve wideband. Finally, a Type-II fractal with an L-Shaped boundary is used to enhance the bandwidth to a greater extent. The gain of the proposed antenna ranges from 4 dB to 6.3 dB for the entire frequency range of 6.2 GHz to 14 GHz. The radiation efficiency of the antenna is noticed up to 84%. The fractal antenna resonates well throughout the entire frequency range with a VSWR of less than 2. The antenna having such a wide band characteristic can be found suitable for a wide range of applications like earth exploration satellites, fixed satellites, radiolocation, maritime radio navigation, and aeronautical radio navigation. A metal reflector is also introduced at the bottom of the antenna to produce a unidirectional radiation pattern. This increases the gain up to 9.8 dBi and a front-to-back ratio is noticed above 20 dB. The design is fabricated and the measurement results are found to be in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

In this paper a new method of applying Chebyshev distribution for series fed antenna array was proposed for radar applications. The first part of this study consists of applying the proposed method on antenna arrays working at 2.3 GHz (S-band radar applications) with 6, 8, 10, 14, and 28 elements, whereas the second part of the study is applying the method on antenna arrays working at 5.2 GHz (C-band radar applications) with the same number of elements. The achieved sidelob level is around (19.6-24 dB). The obtained antenna gain is around (10-17.4 dB) depending on the number of elements. Whereas the horizontal half-power beam width is around (7° - 20°). [ABSTRACT FROM AUTHOR]

In this article, a novel design of a quadband parasitic hat microstrip antenna is proposed for multiband applications. The proposed antenna consists of a rectangular patch of dimensions 30 mmχ11 mm cut with four L-shaped slots connected with a rectangular slot in the middle of the front side of the antenna to form a parasitic hat based upon defected microstrip structure. On the other side of the antenna, a defected ground structure is integrated as five rectangular slots embedded in the ground plane with the same width but with various lengths. The suggested antenna is designed and fabricated on a substrate material with an area of 45 χ 40 mm2 with a thickness of 1.52 mm to generate four frequency bands. The proposed antenna is fed by a microstrip transmission line. The simulated radiation patterns, return losses, maximum gains, and efficiencies of the antenna are carried out by using electromagnetic simulation software based on the finite element method. The measured return loss results validate that the suggested antenna can be designed to cover the frequency ranges from (3.8464 to 4.1456) GHz for sub-7GHz 5G applications, (6.7 to 7.162) GHz for ultra-wideband applications, (9.1616 to 9.5187) GHz for maritime radio-navigation positioning systems, and (11.5421 to 16.4085) GHz for radionavigation satellite standards. The suggested antenna is based upon defected ground structure and defected microstrip structure techniques to improve the antenna performance. [ABSTRACT FROM AUTHOR]

A compact coplanar waveguide (CPW) fed cauliflower-shaped antenna is presented and discussed in this paper. To extend the impedance bandwidth and to improve the impedance matching, fractal geometry having a cauliflower shape is introduced along the edges of the radiator. To validate the simulated results by experimental ones, a prototype of the designed antenna was fabricated on the RO-4350B substrate having a compact size of 0.36230 × 0.410 × 0.015240 at 3 GHz. An Agilent 8722ES vector network was used for the reflection coefficient measurement revealing that the - 10 dB bandwidth of the fabricated antenna offers an impedance bandwidth of 113% extending from 3.05 to 10.96 GHz. Besides, the antenna's radiation patterns are measured in an anechoic chamber showing consistent radiation patterns characteristic over the entire working band. Furthermore, the proposed antenna has a peak gain of around 6 dBi and an average radiation efficiency almost over 90% across the entire operating band. Thus, the proposed antenna could be useful in many modern ultra-wideband (UWB) communication systems. [ABSTRACT FROM AUTHOR]

The implantable antenna is an important part of the wireless capsule endoscopy (WCE) system to achieve wireless communication. This paper designed an ultra-wideband flexible implantable antenna for wireless capsule endoscopy system. With a very wide bandwidth, the antenna can completely cover the industrial, scientific, and medical frequency bands (ISM, 2.4-2.48 GHz) and Wireless Medical Telemetry Service (WMTS, 1.395-1.4 GHz). The expanded size of the proposed antenna is 18mm× 10mm× 0.1mm. The conformal technology of the antenna has further reduced the space of the system and achieved miniaturization. The capsule antenna in this paper is a compact planar monopole antenna fed by a coplanar waveguide, and it uses a flexible material as a dielectric substrate to achieve the conformal shape of the antenna. U-shaped ground branch (UGB) and a loaded split ring resonator (SRR) structure were used to further improve the antenna performance. Simulation and measurement results were basically the same. On the premise of radiation safety and miniaturization of the antenna, the ultra-wideband operation of the antenna was realized. This antenna design provided reference value for the design and application of the capsule antenna. [ABSTRACT FROM AUTHOR]

This paper studies a fuze radome system applied to millimeter waves. The system consists of feed antenna, radome, planar FSS array or curve conformal array. Microstrip antenna is used as the feed antenna. Based on the principle of equispaced and equal period respectively, cross units loading single layer dielectric form planar and curve FSS array. The FSS radome system can improve the permeability of hood to electromagnetic waves (EM) of passband, and reduce the interference of complex EM in the external environment to the system. The FSS radome will not deteriorate radiation characteristics of the feed antenna. The planar FSS radome has a passband of 98.2 GHz to 101.55 GHz with -10dB relative bandwidth of 3.35%. The curve FSS radome has a passband of 96.3 GHz to 101.8 GHz with -10dB relative bandwidth of 5.5%. In addition, the radiation characteristics of the proposed system are analyzed. It is found that the radiation pattern of the antenna is basically consistency before and after loading the radome. [ABSTRACT FROM AUTHOR]

This paper reported a pioneering 5G multiband microstrip line fed patch antenna for IoT, wireless power transfer (WPT) and data transmission. The proposed antenna is accomplished using a triple L-arms patch antenna responsible for the multiband response. A diamond-shaped ground slot is added to control and increase the bandwidth of the resonant frequency. The antenna is designed to resonate at 10, 13, 17 and 26 GHz with 10 dB impedance bandwidths of 0.67, 0.8, 2.45 and 4.3 GHz respectively. The proposed antenna is fabricated using microstrip technology with total area of 16.5x16.5 mm². The 5G multiband antenna has sufficient realized gain of 4.95, 5.72, 4.94 and 7.077 dB respectively. The antenna is designed and simulated using the CST Microwave Studio Suite (Computer Simulation Technology). Measurements show good agreement with simulations in all frequencies of operation. [ABSTRACT FROM AUTHOR]

A dual-notched bands ultra-wideband (UWB) antenna with coplanar waveguide (CPW) fed is presented in the paper. The two notched bands are selected at 3.5 and 5.8 GHz frequencies to overcome the interference from WiMAX and WLAN bands. The overall size of the antenna is 17.5×17.5 mm2, which can be considered as one of the smallest UWB antennas in the literature. The developed antenna has an impedance band width ranging from 2.9 to 13 GHz. The measured radiation patterns on E and H planes are nearly omni-directional and stable with acceptable gain over the entire band. The dual-band notched at WiMAX and WLAN is created by embedding I-shaped and C-shaped stubs in the radiation patch of the antenna. Due to the compactness, good radiation patterns and the reasonable stable gain, this antenna is well suited for integration into portable wireless communications devices for UWB applications. [ABSTRACT FROM AUTHOR]

A frequency reconfigurable planar monopole antenna for fifth-generation (5G) mobile communication terminal equipment is presented. The proposed antenna uses a meandered monopole, branch resonance and other techniques to make the antenna resonant in multiple frequency bands. The antenna is compact in size (115 mm × 55 mm × 0.8 mm) and has a longitudinal length less than one-tenth of the resonant wavelength (working at 1.79 GHz). The pin diode is designed between the planar meandered monopole antenna and branch. The current path of the high-frequency current on the antenna can be easily controlled by controlling the DC bias voltage of the diode, and the operating frequency of the antenna is switched between three frequency bands. The antenna is fed directly through a 50 Ω matched transmission line. The measured data of the antenna in the anechoic chamber show good consistency with simulation data. The radiation pattern of the antenna shows good omnidirectional characteristics and good frequency characteristics, with a maximum radiation gain of 13.6 dBi. Experimental results demonstrate that the antenna can meet the design requirements of 5G communication. [ABSTRACT FROM AUTHOR]

Design procedure of a high gain dual-band printed monopole antenna, resonating at 2.4 GHz and 5.5 GHz, is presented. The proposed design meets the specifications required by WI-FI, WIMAX and radio frequency identification (RFID) reader applications. Our design utilizes Rogers RT/Duroid 5880(tm) substrate, and the major radiation element is an annular circular patch shape. The design was improved by adding a face-to-face fork shape metal inside the annular circular patch. The antenna feed consists of a microstrip line and a slotted transformer section for matching purpose. A prototype of the proposed antenna was fabricated and the measurements of the return loss and antenna radiation pattern were performed. The comparison between the results obtained from the simulation and the measurements showed an excellent agreement. [ABSTRACT FROM AUTHOR]

This study proposes a new omega-shaped tag antenna with inductively-coupled feeding (ICF) using U-shaped stepped- impedance resonators (SIRs). It aims at improving the performance of the tag antennas for Radio Frequency Identification (RFID) applications. The radiating body of the antenna is fed using two mirroring symmetrical U-shaped SIRs. This antenna is a simpler alternative for the existing antennas that match the impedance of the antenna to the chip impedance effectively applying varied reinforcement of the equivalent inductance of the radiating structure. In addition to the use of an omega-shaped structure, the proposed feeding technique boosts performance of the antenna impedance, dimensions, and peak gain. The measured size of the antenna was 50×55.55×1.6 mm3. It attains a peak gain of 1.8 dBi and radiation efficiency higher than 85% at its operating frequency. The experimental results revealed that this tag antenna has the characteristic of good impedance matching within the frequency range of 900-940 MHz, corresponding to a better power reflection coefficient of -3 dB. Comparison between the measured and simulated results verified that the proposed feeding method is capable to improve overall performance of RFID tag antennas. [ABSTRACT FROM AUTHOR]

A single fed circularly polarized reconfigurable patch antenna is proposed. The antenna consists of a radiating patch incorporated with an Hshaped slot at its center. Four ultra-miniature switches are used for polarization reconfiguration. The antenna is designed to operate at the center frequency of 2.357 GHz. The antenna achieves either left-hand polarization or right-hand polarization depending upon switching of corresponding switches. The antenna parameters are simulated using Ansoft high-frequency structure simulator and are validated using an Agilent network analyzer (N9925A) and antenna test systems. The antenna achieves a good impedance match of 120MHz between 2.26GHz - 2.38GHz band and achieves low crosspolarization isolation of -22.82 dB for RHCP and -21.77 dB for LHCP configurations at its operating frequency. The antenna finds application in areas of modern wireless communication. [ABSTRACT FROM AUTHOR]

A quad-ridged horn antenna with dielectric loading covering the 0.6 GHz to 4 GHz band is proposed. Through the comprehensive design of differential feeding, a quad-ridged flare and loaded dielectrics, the feed antenna can be used to match a reflector with a large illumination angle of approximately 150 degrees. In the working band, the reflection coefficient is less than -8 dB, the isolation is larger than 40 dB, and its crosspolarization discrimination is larger than 31 dB for both polarizations. To verify the simulations, a prototype is fabricated and measured, and the measurements are in good agreement with the simulations. A reflector with a diameter of 33 meters and a focal diameter ratio of 0.33 is adopted to analyze the in-dish performance of the feed. The simulated results show that an average efficiency of 55.16% is realized and that the problem of the efficiency decrease caused by beamwidth narrowing at high frequencies is solved. [ABSTRACT FROM AUTHOR]

In this paper, a low profile miniaturization low frequency sleeve monopole antenna loaded with passive lumped (PL) elements is proposed, which can be utilized for HF, VHF, UHF, and P band applications. The proposed antenna is fed by coplanar waveguide (CPW) and composed of feeding line, modified T-shaped radiation patch, sleeve structure and loaded passive lumped elements. An original monopole antenna is operating at 231 MHz with a small fractional bandwidth of 31.8%. By modifying the T-shaped radiation patch and adding the sleeve structure, the fractional bandwidth can be improved by 11%. To further enhance its performance, several passive lumped elements are integrated with the antenna. The design procedure is presented and analyzed in detail. The simulated results demonstrate that a fractional bandwidth of 192.2% from 10-500 MHz can be achieved for the proposed antenna system, which is also in agreement with the measured result. Index [ABSTRACT FROM AUTHOR]

This paper presents several innovative techniques for the design and optimization of a dual band, octafilar helix antenna. The technical challenge of this design is how close the two bands of operation are, as well as the requirement to fit inside a radome with .07λ diameter and .33λ length. This was achieved through a novel technique of applying differing pitches and terminations to the upper and lower frequency antenna filars and then feeding them from a similar location at the base. This allowed for optimal current distribution on each of the two antenna filars. The final design produced gain greater than 0dBic at zenith across both bands of operation. The techniques discussed in this paper were seen to grow low frequency performance by as much as 2.5dBic over a typical octafilar design of the same size. [ABSTRACT FROM AUTHOR]

The design and performance analysis of a single fed reconfigurable patch antenna for circular polarization is presented. The patch has a square shaped slot etched on it. Four ultra-miniature diode switches are placed at appropriate positions to bridge the gap in the slot regions and are used to switch the nature of polarization between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). The antenna achieves an impedance bandwidth (S11 = -10dB) between 2.34 GHz to 2.4 GHz (2.53%) with a center operating frequency of 2.37 GHz. The surface current distributions on the radiating patch along with its corresponding radiation patterns measured at the operating frequency are plotted. The antenna achieves an axial ratio beam width (AR = 3dB) of -25° to 50° for left-hand circular polarization and -40° to 45° for righthand circular polarization. Measured radiation pattern results show the antenna has a good cross-polarization isolation of -16.2 dB for RHCP configuration and -16.54 dB for LHCP configurations and hence the antenna is suitable for modern wireless applications. [ABSTRACT FROM AUTHOR]

Dual-band antenna is very essential for multiple band communication systems like wireless local area network (WLAN) with lower and upper operating bands. In this paper, a dual-band antenna is proposed and analyzed for the WLAN applications. The proposed antenna fed by coplanar waveguide (CPW) consists of an L-shaped, reversed L-shaped strips and two inverted U-shaped loadings that are to implement the reactive characteristics. The reactive loadings can adjust the bandwidth and performance of the dual-frequency WLAN antenna that is verified by the simulation and measurement, respectively. The results demonstrate that the -10dB impedance bandwidth of the proposed dualband antenna can cover the two WLAN frequency bands from 2.4 GHz to 2.484 GHz and from 5.15 GHz to 5.35 GHz, respectively. Moreover, the proposed antenna has omnidirectional radiation patterns at the two operating bands. [ABSTRACT FROM AUTHOR]

This paper introduces a W-band dualpolarization reflector antenna which combines one dualpolarized transmit-receive SUM channel and two singlepolarized DIFF receiving channels. The feed of the antenna consists of four OMTs (Orth Mode Transducer) to realize dual-polarization monopulse angle measurement. Four horns of the feed are combined into one radiation aperture by a coupled retracted structure to decrease side-lobes. The SUM beam gain of the proposed antenna is over 41 dBi and the aperture efficiency of 60% is achieved, cross-polarization level is better than –43 dB. The first sidelobe level is better than -30dB. The nulldepth is better than -20dB. [ABSTRACT FROM AUTHOR]

In this paper, a genetic algorithm (GA) is used to synthesize and optimize the excitation weights of a planar array for satellite communications based on ITU Radio Regulations 2016. The planar array is arranged into symmetric square lattices of subarrays. Each subarray is assumed to be consisting of 4×4 isotropic, uniformspaced, and uniform-weighted elements. The proposed arrays are assumed to be consisting of 4×4 and 16×16 subarrays. A genetic algorithm is used to optimize the weights at the subarrays. Three different cases are studied in the paper. The first case is dealing with an amplitude-only weighting synthesis of the planar array. In this case the ratios of amplitude weights of subarrays are varied continuously from 0 to 1. In the second case, a phase-only synthesis of the planar array is discussed where the phases are varied in a continuous range between -p/2 and 0° while the amplitudes of all subarrays are the same. In the third case a complex weight synthesis is presented. In this case the ratios of the amplitudes are constrained between 0.7 and 1 whereas the phases are varied continuously from -p/2 to 0°. Moreover, the amplitude is varied with both continuous and discrete values. A comparison between the three methods is presented to develop the optimum technique for feeding an antenna array for satellite communication systems. [ABSTRACT FROM AUTHOR]

In this paper, a novel broadband high-gain, circularly polarized planar lens antenna is presented. We used the rotation elements to design a transmission-type polarization conversion planar phase-gradient metasurface (PPGM). By adjusting the rotational angles of the metal patch on the element, we obtained the desired transmission phase shift for PPGM. We used a patch antenna as a feed source, which formed a lens antenna system integrated with the PPGM. The simulation results showed that the PPGM can achieve a high-efficiency, cross-polarization conversion for vertical incidence of a right-handed circularly polarized plane wave. Our numerical and experimental results agreed well with each other, indicating that the antenna system had a peak gain of 18.8 dB, a good axial ratio better than 2 dB at 13 GHz, with an aperture efficiency of 50.56% and a focal length/diameter (F/D) ratio of 0.307. In addition, its -10 dB impedance and 3dB axial ratio bandwidth reached up to 940 MHz. The lens antenna performed well and can be applied in many communication systems. [ABSTRACT FROM AUTHOR]

In this paper, a wideband dual-polarized microstrip antenna is proposed inspired by the concept of the periodic grid-slotted surface. Inherited the merit of low profile from microstrip antenna, a relatively wide bandwidth, i.e., up to 43% with reflection coefficient less than -10 dB, is achieved for both orthogonal polarizations. Multiple modes are excited due to the periodic slot-loaded structure and well matched using crossed aperture-coupled Y-shaped feeding. The overall height of the proposed antenna is only 0.06 λ0, λ0 is the free-space wavelength at the centre frequency of 5.5 GHz. The proposed antenna is systematically studied in the numerical simulation and experiment, and results agree well. The proposed dual-polarized antenna provides an effective choice for wideband low profile antenna for the applications of base station. [ABSTRACT FROM AUTHOR]

In this paper, a reconfigurable antenna feeding network using coupled line switches for 5G communication system is presented. Two quarter-wave impedance transformers were integrated to support TDD operation and a single stage coupled line filter was used as a DC block for RF switches instead of using conventional surface mounting components. Design equations and theoretical analysis for the proposed reconfigurable antenna feeding network are also presented. To demonstrate the performance of the proposed reconfigurable antenna feeding system for MIMO, two monopole antennas were integrated orthogonally to the designed feeding network. Vertical or horizontal polarization was successfully formed and the radiation pattern can be selectable by manipulating the switches. [ABSTRACT FROM AUTHOR]

In this paper, E-shape microstrip patch antenna for wireless communication is designed, simulated, built and tested. The operating frequencies of antenna are 2.97 GHz and 4.85 GHz, the substrate FR4 is used for proposed antenna with dielectric constant 4.01 and 1.7mm thickness. Two parallel slots are cut to perturb the surface current path to achieve dual resonance. The E-shape has return loss of -28 dB and -14.03 dB at operating frequencies 2.97 GHz and 4.85 GHz respectively. Designing and simulation of this antenna has been done by the help of Sonnet Software. This antenna is fed by a co-axial probe feeding. In this paper, the effects of length difference among antenna legs has been studied. [ABSTRACT FROM AUTHOR]

Design and performance of a shaped beam 12.2 GHz array-fed reflector antenna for broadcasting satellite is presented in this paper. Initial design, employing a cluster of feed horns illuminating a parabolic reflector is initially proposed for multi beam antenna (MBA) system to produce a contoured beam for Peninsular Malaysia. The precise feed positions are determined through a newly developed ray tracing program. Due to the small size of the coverage area, an issue with regards to physical constructability of the feed horns is raised. The MBA is modified by utilizing 18- element microstrip array as the feed, where each element positions are calculated by using the same caustic model. In this case, the preceding issue is solved, and high gain shaped beam coverage with uniform aperture is generated. This paper shows the results of the contoured beam antenna that have been achieved for beam scanned over a coverage size of approximately 0.9° long and 0.5° wide. Small variation of radiation level, which is less than 3dB within the edge of coverage (EOC), is also demonstrated in the performance analysis. [ABSTRACT FROM AUTHOR]

A dual-polarized log-periodic antenna with 5:1 bandwidth is considered for wideband, amplitude only direction finding applications. The proposed system is comprised of two identical, orthogonal, sets of trapezoidal log-periodic arms. The arms’ inclination from planar facilitates reduced back lobe radiation to improve directivity and efficiency once absorber is introduced. One arm of each polarization set contains a variable radius coaxial shell to achieve impedance matching such that the system impedance at the base of the antenna is matched to 50 ohms. Analysis and design for the 3d printed direction-finding antenna system is accomplished using a commercial off the shelf (COTS) finite element method (FEM) solver. [ABSTRACT FROM AUTHOR]