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A broadside direction gain-enhanced low-cost dual-polarized microstrip patch antenna has been presented. The proposed antenna consists of a slot-loaded cross-shaped patch and shorting pins. The orthogonal polarized radiating elements works in TM05 and TM12, meanwhile slot-loaded excite TM01. The equivalent magnetic currents (EMCs) amplitude, frequency, and flow direction of the TM12 are controlled by shorting pins to form the broadside gain enhancement. The superposition of them can enhance the gain in the broadside direction. The proposed antenna is coaxial feed. The substrate is divided into two layers: air and FR4. A copper column is added to the air layer to greatly improve the polarized isolation of the antenna. The size of the proposed antenna is 2.29λ0×2.29λ0×0.069λ0 (λ0 is the wavelength of free space at the central frequency). The simulated maximum realized gain is 12.59 dB, and the realized gain is better than 11.53 dB in operating band. The measured maximum realized gain is 12.05 dB, and the realized gain is better than 10.04 dB. The dual-polarized microstrip patch antenna has the advantages of low cost and high gain, which can be used in the modern wireless communication system. [ABSTRACT FROM AUTHOR]

Dual polarization is achieved by putting a rectangular or circular patch in between two orthogonal gaps. At the beginning a single-polarized patch is considered. Then by using anequivalent circuit, the impedance matching property of the gap is being configured. After optimization of the length of the patch and width of the gap, a dual polarized antenna is being considered. Here in this article we projected a new technique to design dual polarized microstrip antenna for WLAN, WiMAX, wireless applications using circular patch. By combining all resonant modes we have finally achieved a wide operating bandwidth. Experimental result of the projected antenna shows the operating bandwidth of 21.56% (5.24–6.37 GHz) for (differential mode S-parameter) Sdd11 ≤ −10 dB with a high port isolation of 40 dB and a relative gain of 13.5 dBi is achieved. From the result analysis this antenna finds its applications for various WLAN and Wi-MAX frequency band. [ABSTRACT FROM AUTHOR]

This article proposes a low-profile, dual-polarized $4\times 4$ antenna array for the fifth-generation (5G) applications. It originates from our previous linear-polarized design, but with two split dipoles. For each polarization, the current on the split dipoles will cancel each other out in one direction. In contrast, in the orthogonal direction, the current can be regarded as a driven dipole to couple energy to four parasitic patches. The proposed element has a profile of only $0.073\lambda _{0}$ (where $_{\mathrm {}}\lambda _{0}$ is one free-space wavelength at 27.85 GHz) with simulated standing wave ratio (SWR) < 2 from 22.11 to 33.6 GHz (BW ≈ 41.25%). The average gain is 8 dBi, and the peak gain reaches 10 dBi at approximately 31.5 GHz. Besides, the two polarizations possess almost the same performance due to the symmetry of the antenna. A 4 $\times 4$ antenna array is designed, simulated, and experimentally demonstrated based on a subarray that can support two orthogonally mode excitations. The measured results present an overlapped bandwidth of 28.4% and more than 25 dB isolation. In addition, the maximum gains are up to 19 and 18.9 dBi for Ports 1 and 2 excitations, respectively. Our proposed design has great application potential in vehicle-mounted millimeter-wave radar and 5G communications systems. [ABSTRACT FROM AUTHOR]

Summary: To obtain the polarization agility in wireless applications, the dual polarized wideband or multi‐band antennas are required. In this paper, modified designs of square microstrip antenna by employing overlap offset parasitic patches are proposed for the dual polarized wideband and multi‐band response. Due to the optimum spacing in between the fundamental TM1045 and TM01135 modes along with TM11 mode, on a total substrate thickness of 0.075λg, the proposed design yields bandwidth of more than 550 MHz (>50%), exhibiting the dual polarized characteristics. A similar design is presented on a thinner suspended substrate. Here, on the substrate thickness of 0.035λg, it yields impedance matching at higher order TM20 mode, which along with TM1045, TM01135, and TM11 modes exhibits triple band response. An impedance bandwidth of 3.4%, 17%, and 4.7% is realized in the three bands with a broadside gain of more than 6 dBi. The proposed design satisfies the requirements of GSM 810/GSM900/LTE applications. In each design, simulated results have been experimentally verified that show close agreement. [ABSTRACT FROM AUTHOR]

This paper reports a bi-port, wideband, parasitic-fed, single/shared patch antenna with enhanced interport isolation for 2.4 GHz in-band full duplex (IBFD) applications. The employed parasitic feeding provides comparatively the wider impedance bandwidth and better gain for the presented antenna. The improved self-interference cancellation (SIC) levels across the required bandwidth are obtained through differentially-driven receive (Rx) mode operation. The differential Rx operation performs effective cancellation of in-band self-interference (SI) through signal inversion mechanism to achieve the additional isolation on the top of the intrinsic isolation of polarization diversity. The validation model for the presented antenna features ≥88 dB peak isolation between the dual-polarized Tx and Rx ports. In addition, the measured Tx–Rx isolation for prototype is >70 dB across the 10 dB return loss bandwidth of 100 MHz (2.42–2.52 GHz). The measured gain for each mode is better than 7.0 dBi. The novelty of this work is that compared to previously reported designs, the presented antenna offers wider impedance bandwidth and improved SIC levels in addition to superior gain performance. To the best of our knowledge, this is the first single/shared patch antenna which provides better than 70 dB interport isolation across the 10 dB return loss bandwidth of 100 MHz along with 7.0 dBi gain for Tx/Rx modes. [ABSTRACT FROM AUTHOR]

In this letter, a 4 × 6 microstrip patch array antenna with a low sidelobe level (SLL) for dual linearly polarized synthetic aperture radar (SAR) is proposed. The low SLL in wide-band is obtained by implementing the Chevyshev taper distribution. An optimal approach to design an unequal-power symmetric microstrip divider for dual-polarization is employed in the same layer with high isolation between the polarizations. The proposed antenna consists of squared patches excited by aperture coupled slots. With the analysis of resolution, swath, and noise equivalent sigma zero (NESZ) of the SAR system, we selected the antenna parameters such as bandwidth, beamwidth, gain, and SLL. The proposed antenna has a more than 10 % bandwidth and peak gains of 18.2 dBi and 18.3 dBi in V and H-polarization, respectively. The measured SLL in both polarizations are under −21.1 dB in the E-plane and −17.0 dB in the H-plane at the 10 GHz. [ABSTRACT FROM AUTHOR]

Multi-band microstrip antennas have been commonly realized by using techniques of stub or slot. In these designs, knowledge about correct positioning of stub or slot and their effects on patch resonant modes in terms of their frequency and impedance variation is needed. In this paper, with reference to a variation of slot cut circular microstrip antenna, a detailed study that provides an insight into functioning of multi-band dual polarized antenna is presented. The slots degenerate patch first two resonant modes into dual orthogonal modes to give multiple frequency response with dual polarization. The resonant length formulations at modified degenerated circular patch modes are presented. The frequencies calculated using them match closely with the simulated frequencies. For gain enhancement, air suspended design of slot cut antenna is presented which gives broadside gain of 1.5 to 6 dBi across multiple frequencies. Thus, the present work explains the functioning of multi-band antenna in terms of patch modes and will serve as a tutorial for analyzing similar multi-band dual polarized configurations. [ABSTRACT FROM AUTHOR]

In this article, a hybrid resistive metasurface (RM) based on the different field distributions of radiation and scattering is designed and realized for dual‐polarization radar cross section (RCS) reduction of patch array antenna without enlarging its original dimensions. The hybrid RM is composed of two RMs located on the same plane, which is both transmissive for electromagnetic waves from antenna below at resonant frequency of 12.3 GHz. The combination of the RMs and the metal ground of antenna form absorbers, which absorb in‐band co‐polarized (RM1) and cross‐polarized (RM2), waves respectively. The hybrid RM is arranged by RM2 placed directly above the radiation patches while RM1 placed elsewhere. Therefore, the radiation performance of antenna is basically unaffected meanwhile realizing the in‐band dual‐polarization RCS reduction. Simulation results demonstrate that the hybrid RM exhibits RCS reduction of co‐polarization and cross‐polarization reaches 10.7 and 3.3 dB respectively by the window‐like layout, and main lobe gain achieves to 18.0 dB, which is 2.2 dB lower than that of reference antenna. The experimental results are consistent with the simulation results in the main. [ABSTRACT FROM AUTHOR]

Dual polarized triple frequency wideband design of circular microstrip antenna using the combination of slots and stub is proposed. This triple wideband response is explored by using a thinner substrate in the air suspended configuration that enables the input impedance matching at various higher order resonant modes together with the fundamental mode. Amongst different variations, modifications in terms of the slots and stubs degenerates and optimizes the spacing in between the fundamental and higher order modes, which leads to dual polarized wideband response. On air suspended FR4 substrate with thickness of 0.055λg, optimized single patch configuration yields dual polarized triple wideband response at 856, 1177, and 1783 MHz respectively giving frequency ratio of 1:1.37:2.0. It yields impedance bandwidth of 8.4%, 11.5%, and 11.4% at the three frequencies with respective broadside gain of 7.4, 6.5, and 3.5 dBi. The proposed configuration yields frequency and polarization agility satisfying the requirements of GSM850/navigation satellite/GSM 1800 applications. [ABSTRACT FROM AUTHOR]

Design of compact P-shape microstrip antenna for dual polarized wideband response is proposed. The two stubs placed on the edges of the P-shape patch optimizes the spacing in between the higher order TM01 and TM20 modes with respect to the fundamental TM10 mode that yield a bandwidth of more than 800 MHz (>65%). On air suspended substrate, the antenna exhibits broadside gain of more than 7 dBi over the impedance bandwidth. The orthogonal surface current variations across the TM10, TM01, and TM20 modes realize polarization agility satisfying the requirements of GSM900/LTE applications. With respect to the band start frequency, the proposed configuration offers a 5% reduction as compared with the equivalent rectangular microstrip antenna. The formulations in resonant length are derived by defining the resonant length at each P-shape patch mode. The P-shape antennas re-designed using them at given fundamental mode frequency yield similar dual polarized wideband response offering a bandwidth of > 60%. [ABSTRACT FROM AUTHOR]

This letter discusses the design of a dual-polarized four-element linear antenna array with increased port-to-port isolation, intended for base stations of single-channel full-duplex systems. The antenna is designed for the U-NII 5.15–5.925 GHz frequency band and is characterized by port-to-port isolation higher than 57 dB and cross polarization better than –27 dB within the mainlobe. An electromagnetically coupled microstrip antenna is used as a single element of the antenna array. Enhanced isolation is obtained owing to the multilayer antenna structure and special feeding network utilizing the pairwise antiphased feeding technique combined with a careful selection of phase-shifters and power dividers. The antenna parameters are optimized with the use of full-wave simulations, while the scattering parameters and radiation characteristics are verified by measurements. [ABSTRACT FROM AUTHOR]

Multiband response is commonly realized using microstrip antennas preferably using slot or stub. Patch resonant modes get highly affected in terms of their frequency and impedances with respect to proper selection of dimensions and positioning of slots or stubs. In this paper, a multiple slots loaded rectangular microstrip antenna is proposed for dual polarized multiband response. Slot position and dimension tunes higher order modes TM02 and TM12 with respect to fundamental mode TM10 realizing dual polarized multiband response with impedance bandwidth of 1.5% to 2% at each band. Frequencies calculated using proposed resonant length formulations for each mode closely match with the simulated one. For gain enhancement Arlon substrate design is proposed which gives broadside gain of 2.5 to 4.7 dBi across multiple frequencies. [ABSTRACT FROM AUTHOR]

Novel design of multi-band Crescent shape microstrip antenna is proposed. Modifications in equivalent circular patch yields new resonant modes nearer to the TM11 and TM21 modes in circular patch that gives four band frequency response showing dual polarizations. Proposed design gives 1 to 1.5% of bandwidth at each frequency with broadside radiation pattern. The resonance frequency equation by defining the resonant length at each mode in the Crescent shape patch, is proposed. The frequency calculated using the same agrees closely with simulated result. The air suspended design of crescent shape patch is presented which yields co-polar peak gain of above 1.5 dBi. [ABSTRACT FROM AUTHOR]

A high‐selectivity dual‐polarization filtering antenna with metamaterial is presented in this letter. The multilayer coupled radiation structure of the antenna determines a filtering function. With the metamaterial layer designed above the antenna, a sharp roll‐off rate at high pass band edge and a better out‐of‐band rejection occurs, thus a better high selective filtering characteristic can be achieved. Simulating and measuring the antenna, the impedance bandwidth (VSWR <2) of the antenna is from 3.25 GHz to 3.85 GHz; meanwhile, the maximum gain can reach 9dBi. The gain of antenna can quickly decrease 43dBi at the high pass band edge from 3.85 GHz to 4.05 GHz and the antenna has an out‐of‐band rejection level of 27dBi from 4.05 GHz to 5 GHz. The tested results verify our designs and the antenna could be a good candidate for the 5G anti‐interference wireless terminal communication system. [ABSTRACT FROM AUTHOR]

Abstract Design of compact multiple slots cut F-shape microstrip antenna for broadband dual polarized response is presented. The multiple rectangular slots in F-shape patch, tunes the resonance frequency and impedance at second order TM 20 mode with reference to the fundamental TM 10 mode, that yields bandwidth of more than 500 MHz (>40%). Because of orthogonal current variations across TM 10 and TM 20 modes, F-shape patch yields dual polarized wideband response. The bandwidth of individual polarization is governed by the stub length in F-shape patch. Proposed antenna exhibits broadside radiation pattern over the bandwidth with gain of more than 6 dBi at two resonant modes. [ABSTRACT FROM AUTHOR]

A compact single-polarized filtering dielectric resonator (DR) antenna (DRA) with high selectivity is investigated. The DRA is fed by hybrid microstrip line/conformal strip, excited in its fundamental TE $_{1\delta 1}^{y} $ mode. Owing to different loading effects of the microstrip stub and conformal strip, the resonance frequency of TE $_{1\delta 1}^{y}$ mode excited by the two feed lines is slightly different. Such stepping resonances yield a wide bandwidth of 21.9% and a very flat gain of 5.1 dBi. The hybrid-feeding scheme also establishes a cross-coupled structure in the DRA, which introduces two radiation nulls right near the band edges. A compact wideband filtering DRA (FDRA) with quasi-elliptic bandpass response is, therefore, obtained without requiring any specific filtering circuit. This single-polarized design is also modified to realize a dual-polarized FDRA by adding another orthogonal port with the same feeding scheme. To reduce mutual coupling between the two ports, the microstrip stubs are folded to L shape, and four additional metal posts are inserted into the DR. As a result, the isolation is improved by 14 dB, from 7.2 to 21.2 dB. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present a compact dual linear polarized cavity‐backed patch rectenna for optimized wireless RF power transfer with DC power management network. The proposed rectenna is composed of a minimized patch radiator with a backed cavity, the feeding network and a rectifying circuit with DC power management network. The minimized patch radiator with the backed cavity reduces the physical size and enhances the bandwidth. The feeding network is designed to receive all kinds of polarized waves. The rectifying circuit converts received RF energy to DC energy and effectively combines DC energy from each polarization port by DC power management network. The DC power management network also properly operates a load with certain constant voltage. The proposed rectenna is simulated and measured to verify the performance. Each antenna shows about 5.3 dBi peak gain and each rectifying circuit shows about 50% RF to DC conversion efficiency at 0 dBm input power. Due to dual linear polarization, it is observed that received output efficiency is larger than 46% regardless of incident polarization angle. [ABSTRACT FROM AUTHOR]

A compact four-unit ultra-wideband multipleinput multiple-output (UWB-MIMO) antenna with very high isolation, dual polarization, notched structure, and achieving dual-state operation, along with smaller volume, is proposed in this paper. The proposed MIMO antenna element consists of two parts: the front patch composed of four symmetrical trapezoidal radiating elements and feeder, and the back composed of a rectangular annular ground. The offset of antenna operating frequency band is achieved by adjusting the rectangular patch in the middle of the back side, and by introducing an X-shaped metal narrow strip on the top side and an X-shaped slit on the bottom side to improve the isolation in the single port feeding state of antenna. Finally, the dimension of the antenna is 32 × 32mm2. Under the frequency from 3.1 GHz to 10.6 GHz, the isolation in the condition of differential mode can below -30 dB, which is very high, and also can work in the single port inputting state, showing a dual mode operation. In addition, a trapezoidal slit is introduced to obtain a notch structure. The measured results and simulation results are consistent. [ABSTRACT FROM AUTHOR]

This article presents the design of a novel dual polarized waveguide fed circular microstrip patch antenna for Ku band applications. The circular microstrip patch is fed by using a square waveguide and a cross slot. The cross slot consists two orthogonal slots for coupling the energy associated with two orthogonal modes propagated in the square waveguide, i.e. TE10 and TE01 mode in order to achieve dual polarization. The orthomode transducer is designed for the frequency range of interest in order to separate and combine two orthogonal modes and to connect with two standard WR-51 rectangular waveguides. The design is optimized using the electromagnetic software CST Microwave Studio and the structure with optimized dimensions is fabricated and measured. The measured along with simulated antenna parameters are presented. The designed and developed dual polarized waveguide fed circular patch antenna can be used for Ku band applications. [ABSTRACT FROM AUTHOR]

ABSTRACT A microstrip coupled-fed antenna with dual-band dual-mode and dual-polarization characteristics is proposed in this letter. The antenna consists of two symmetrical rectangular patches as radiators and a microstrip line as coupled feeding structure. TM01 mode and TM10 mode of rectangular patch can be excited simultaneously at different frequencies for different polarizations. The proposed antenna is designed, fabricated and tested. The proposed antenna resonates at 4.3 and 5.4 GHz which are allocated for navigational applications. The measured −10 dB reflection coefficient bandwidth of the two modes are 60 MHz in lower frequency band and 140 MHz in upper frequency band for horizontal and vertical polarizations, respectively. Radiation patterns at two resonant frequencies are measured and compared to simulation results. The proposed antenna has advantages of simple structure, low cross polarization and low cost. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1065-1068, 2017 [ABSTRACT FROM AUTHOR]

A $6 \times 6$ wideband antenna array with ±45° dual polarizations is proposed. To achieve good radiation efficiency, cavity antenna is used in this work as the basic element. Feeding probes and strip line feeding networks are printed on general PCB substrate. The feeding circuits for exciting different polarizations are stacked and multilayer substrate step structure is used. Here, strip line to downward SMA connector transitions is also designed, which aids in integrating the proposed array with T/R modules located below and extending it to larger phased array. The antenna array is fabricated and measured. Simulated and measured impedance and radiation performances are also given and compared. The proposed antenna arrays show wide bandwidth of 30% from 10.9 to 14.8 GHz, and isolation of higher than 33 dB is also exhibited across the bandwidth. Furthermore, symmetrical patterns and cross-polarizations of below −25 dB are also demonstrated. [ABSTRACT FROM PUBLISHER]

A V-shape slot antenna for dual slant polarization is proposed. The slot is the union of two stepped rectangular slots tilted at ±45° with the vertical. Each section of the slot is excited using a microstrip feed line printed on the other side of the substrate. The feed is also stepped and bent so as to cross the slot at right angles. The decoupling between the ports is provided by means of narrow rectangular stubs placed at the intersection of the slot arms. Measurements taken on the fabricated prototype indicate an impedance bandwidth from 3.3 to 12 GHz with isolation better than 15 dB across the band. The aperture electric field distributions as well as far field radiation patterns are used to verify the dual slant polarization achieved with the antenna. The time domain characterization of the antenna is done by calculating the fidelity factor which is found to be >0.75 indicating suitability of the antenna for pulse transmission. For determining the diversity behavior, the envelope correlation coefficient is calculated and found to be below 0.004. The antenna has a peak gain from 4 to 6 dBi. A modified design of the antenna is also presented with impedance bandwidth from 3 to 12 GHz and isolation better than 20 dB from 3.7 GHz onwards. With compact features and wideband return loss and isolation, the antennas are expected to be useful for diversity applications in ultra wideband communication devices such as MIMO wifi, imaging radars, and polarimetric sensing devices. [ABSTRACT FROM AUTHOR]

For obtaining dual-polarization, using a square annular cavity in the ground plane of a broadband microstrip patch antenna, with proximity-coupling as the feeding mechanism, is proposed in this paper. The antenna has four sequentially arranged feed-lines, and each pair of opposite feed-lines in the same direction are excited by antiphase, which provides the high isolation between the two pairs of ports, besides increasing polarization purity. The cavity and the patch act as two radiators, and the square annular shape of the cavity improves their balance, and thus the bandwidth. The design of the antenna, which is based on particle swarm optimization (PSO) algorithm, and the main parameters of the antenna were investigated. To validate the proposed method, a prototype antenna and a feeding balun were fabricated. The measured results show 61% bandwidth (active \textVSWR < 2), high isolation and good radiation patterns. [ABSTRACT FROM AUTHOR]

A dual-polarized slot-coupled microstrip antenna array with stable active element pattern is investigated. The antenna element of the array is a slot-coupled microstrip antenna with a reflector. The effect of the ground size on the radiation pattern of the antenna element is analyzed based on the electric field and current distributions. The method of adding copper pillars around the antenna element is proposed to mitigate the influence of the ground plane. A prototype of 1 \times 3 microstrip antenna array is fabricated and measured. Its measured impedance bandwidth for \mathrmVSWR < 2 is 520 MHz (1.69–2.21 GHz). Within the operating band, the performances of low mutual coupling, low cross polarization, and stable active element pattern are achieved. [ABSTRACT FROM PUBLISHER]

ABSTRACT This article presents a novel design of dual polarized microstrip patch antennas for ultra-wideband (UWB) applications. Two antennas are designed for different frequency band of UWB. Both antennas are loaded together and the combined antenna is designed for the entire UWB. The designed antenna is optimized using CST Microwave Studio simulator. The antennas are fed by a 50-Ω coaxial probe. Both antennas are fabricated and measurement of return loss and radiation pattern is performed. The VSWR 2:1 bandwidth of individual designed Antenna I and Antenna II is 3.1-5.2 GHz and 4.9-11.5 GHz, respectively. The comparison between simulated results and measured results shows good agreement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2174-2179, 2014 [ABSTRACT FROM AUTHOR]

This paper presents a lightweight antenna for wireless communication systems. The proposed antenna has been designed to be a dual-band and dual-polarized antenna by using a right-angled slot structure fed a by microstrip line. The designed antenna is composed of three right-angled slot radiators on the ground plane. The first two radiators are right-angled slots of similar scale which are added to generate circular polarization at 4.95 GHz, while the last one has been designed for linear polarization at 2.45 GHz. Furthermore, in order to achieve dual-band operation and dual polarization with good matching, a special arrangement is proposed. The results of simulation and measurements such as return loss, axial ratio, and radiation patterns are shown at the resonant frequencies of 2.45 and 4.95 GHz. Details of the experimental results are presented and discussed. In addition, the presented antenna can operate and cover the applications of a wireless local area network (WLAN IEEE 802.11 a/b/g/j/n). © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

An isolation enhanced dual polarized microstrip patch antenna has been designed for S-band Synthetic Aperture Radar. This antenna operates at 3.125 GHz with operating bandwidth of 150 MHz or 4.8%. The electromagnetic power is coupled from the feed line to radiating patch through proximity coupling feeding technique for better bandwidth achievement. A centre ground-shorted microstrip line is created at the feeding layer to enhance the isolation of the input ports. The simulation result illustrates the effect of the ground shorted microstrip line to the isolation of horizontal and vertical polarizations. [ABSTRACT FROM AUTHOR]

This article presents the design and development of a new type of wideband shared aperture dual band dual microstrip polarization patch antenna (MPA) operating at L&S band. In this configuration, square ring shaped radiating element at L band and square shaped patch printed on different dielectric substrate layers housed within the square ring at S-band has been used. The probe fed feeding mechanism is employed to get wide bandwidth performance at both bands. The measured 10-dB return loss bandwidth is 28.3% at L band and 29.4% at S-band. The simulated and measured antenna parameters of this antenna are in excellent agreement. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:917-922, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27414 [ABSTRACT FROM AUTHOR]

A novel dual-polarization microstrip patch antenna fed by quasi-cross-shaped slot with high isolation (greater than 50 dB) over a wide bandwidth from 3 to 4 GHz is investigated. Four identical slots—referred to “quasi-cross slot”—are arranged symmetrically in an unconnected cross configuration in the center. The isolation between two orthogonal polarizations of the proposed antenna can be greatly improved over the conventional cross slot. A prototype was fabricated and measured. The maximum achievable gain of the proposed antenna is 9.6 dBi with a gain variation of 0.6 dBi over the bandwidth of 200 MHz (3.4–3.6 GHz). The design is suitable for array application in MIMO system. Details of the proposed design and experimental results are presented and discussed. [ABSTRACT FROM PUBLISHER]

This article presents a new miniaturized reconfigurable slotted microstrip patch antenna with defected ground structure. The antenna operates in two different frequency bands with polarization pattern diversity and broad radiation characteristics. The size reduction of this antenna is more than 34% in comparison to a conventional rectangular patch antenna for two frequency bands. Details of the experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

In this communication, a dual-feed dual-polarized microstrip antenna with low cross polarization and high isolation is experimentally studied. Two different feed mechanisms are designed to excite a dual orthogonal linearly polarized mode from a single radiating patch. One of the two modes is excited by an aperture-coupled feed, which comprises a compact resonant annular-ring slot and a T-shaped microstrip feedline; while the other is excited by a pair of meandering strips with a 180° phase differences. Both linearly polarized modes are designed to operate at 2400-MHz frequency band, and from the measured results, it is found that the isolation between the two feeding ports is less than 40 dB across a 10-dB input-impedance bandwidth of 14%. In addition, low cross polarization is observed from the radiation patterns of the two modes, especially at the broadside direction. Simulation analyses are also carried out to support the measured results. [ABSTRACT FROM AUTHOR]

A new design of a wideband dually-polarized shorted microstrip patch antenna coupled to hook shaped probes is presented. The antenna is designed to operate around 4 GHz. The mechanisms of the shorted microstrip patch antenna provide wider impedance bandwidth over 37%. The shorted patch is smaller than the full unshorted patch. A gain around a 9-10 dBi is achieved within the bandwidth. The present design provides about 40 dB isolation level between the two ports. A stable low cross polarization level of -20 dB is obtained. [ABSTRACT FROM AUTHOR]

A new design of a compact single-feed dual frequency dual polarized microstrip antenna with an X-slot is presented. The proposed antenna generates two orthogonally polarized radiations with center frequencies at 1.42 GHz and 1.79 GHz, respectively. For fixed dual frequency operation, the antenna has an area reduction of 74% and 59% for the respective frequencies compared to standard rectangular patches. The antenna exhibits broadside radiation pattern and has sufficient gain for the two bands. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3198–3201, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23903 [ABSTRACT FROM AUTHOR]

Design and measurement data are presented that show how the novel concept of a traveling-wave-fed circular-polarization (CP) microstrip antenna can be extended to provide an antenna with dual CP. A new refinement to the basic antenna structure is also introduced that shows that the efficiency of radiation can be enhanced by using a dual dielectric to improve the fringing fields at the edges of the radiating patches by around 40%. Furthermore, new theoretical and simulated data are introduced to support the original traveling-wave feed concept. [ABSTRACT FROM AUTHOR]

A dual-frequency and dual-linear polarization multilayer microstrip antenna element for array-antenna applications is presented. The performance of the element was computed using a commercial software based on the finite-element-method (FEM) algorithm. A prototype with dimensions based on the simulations was built and tested. Good agreement between the measured and numerical results is obtained. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 311–315, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20288 [ABSTRACT FROM AUTHOR]

This paper presents multifunctional microstrip transmission lines for designing a high port-isolation dual-frequency orthogonally polarized rectangular patch antenna and the antenna-integrated power amplifier. The proposed lines were realized through the integration of defected ground structures (DGSs) with conventional microstrip lines. A spiral-shaped DGS-integrated microstrip line enhances the port isolation of the antenna, while feeding the 2.0-GHz excitation to the antenna and filtering out the 2.5-GHz receiving signal from the other port. High-order harmonic signal suppression of the power amplifier at the 2.5-GHz port was accomplished by the dumbbell-shaped DGS, thereby improving the efficiency of the amplifier. Measurements show an improvement of 20 dE in port isolation and 3% in power-added efficiency relative to an identical RF front-end, but integrated with a conventional patch antenna. An image impedance of the DGS-integrated microstrip lines can be controlled by the integrated DGS geometries. Relatively high-impedances lines, i.e., 150 and 100 Ω, are effectively implemented using microstrip lines with 75- and 50-&Ohm; linewidths by incorporating the spiral- and dumbbell-shaped DGSs, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the design and development of a compact dual linearly polarized aperture-coupled microstrip patch antenna array system for radio frequency identifications (RFID) applications. Two different antenna designs, Antenna-1 and Antenna-2, for RFID tag and reader applications are presented at the C and S bands, respectively. The antennas use two symmetric coupling apertures to excite two orthogonal modes for dual-polarization operation. High isolation of the order of -35 dB is obtained by proper selection of the shape and positions of the coupling aperture. The prototype antenna yields a 14.6-dBi peak gain, a 36° 3-dB beamwidth (HPBW), a 30-dB cross-polarization level, and isolation better than 38 dB between the two orthogonal polarizations (Tx and Rx) at the S band, and a 7.7-dBi peak gain, a 70° 3-dB beamwidth (HPBW), a 24-dB cross-polarization level, and isolation better than 38 dB between the orthogonal polarization at the C-band, respectively. The antenna yields a 10-m identification-read range in the field trial. The findings are very promising for RFID applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 354–360, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11215 [ABSTRACT FROM AUTHOR]

A new integrated structure of a two-element microstrip patch antenna with two feeds for wireless local network/global positioning system (WLAN/GPS) operations is proposed. The radiating element for dual-band WLAN (2400–2483 MHz and 5150–5850 MHz) operations is a single-feed planar inverted-F antenna with a U-shaped slot, which gives linearly polarized radiation. The second radiating element is a square microstrip patch with truncated corners for GPS operations at 1575 GHz, which provides circularly polarized broadside radiation patterns. The two radiating elements are integrated in the proposed antenna to have a compact structure. In addition, an isolation of better than -25 dB between the feed ports was also obtained. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 120–123, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10990 [ABSTRACT FROM AUTHOR]

Design equations are presented for calculating the resonance frequencies for a compact dual frequency arrow-shaped microstrip antenna. This provides a fast and simple way to predict the resonant frequencies of the antenna. The antenna is also analyzed using the IE3D simulation package. The theoretical predictions are found to be very close to the IE3D results and thus establish the validity of the design formulae. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12, 477–482, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce.10048 [ABSTRACT FROM AUTHOR]

This paper presents a novel printed antenna element capable of providing high-quality radioelectric performance in two frequency bands with a separation ratio in the range of approximately 1:1–1:3. The properties of printed grids are generalized to improve the polarization purity and the band isolation of this dual-band, dual-polarization patch element. A GSM/2DCS patch antenna with slot coupling excitation is described, and the possibilities offered by this technique are discussed. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 265–268, 2000. [ABSTRACT FROM AUTHOR]

A novel design method for an aperture-coupled microstrip patch antenna with a single feeding structure is proposed for dual resonance frequencies with mutually perpendicular polarizations. A new type of square patch with double notches is used as a radiator, and the crossed slot and bended microstrip feeder are adopted for the dual polarizations in the aperture-coupled structure. The characteristics of this antenna were experimentally investigated for generalizing the dual-frequency behavior. A Ku-band Tx/Rx 2×2 subarray antenna was designed and manufactured to examine the applicability as a ground terminal antenna for satellite communications. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 370–374, 2000. [ABSTRACT FROM AUTHOR]

A new low-cost dual-polarized microstrip antenna array with a single layer is proposed. Its element is the parallel corner-fed square patch with two ports. The design, analysis, and experimental results of a 12 GHz 16-element array on a 0.8 mm thick substrate are presented. Its measured isolation is 26.5 dB at 12 GHz and higher than 20 dB over 710 MHz. The 2:1 VSWR bandwidth is wider than 840 MHz (7%). The theoretical results agree well with the experimental results. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 176–179, 2000. [ABSTRACT FROM AUTHOR]

A new dual-polarized microstrip antenna array is presented. Diagonal feeding of the square patch with two ports is proposed to obtain dual linear polarization. A novel coplanar feedline network is also presented for the dual-polarized array. For engineering purposes, a CAD-oriented method of analysis is developed. The measured results demonstrate high isolation between the two input ports. The array has simple structure and is easy to further combine to form larger coplanar arrays. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 42–48, 1999. [ABSTRACT FROM AUTHOR]

A dual-port dual-polarized compact microstrip antenna for avoiding cross coupling between the two frequency bands is proposed and analyzed. This antenna offers channel isolation better than 25 dB, and is more compact compared to a conventional rectangular patch. Analytical equations for calculating the resonant frequencies at both ports are also presented. The theoretical calculations are verified using experimental results. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 125–127, 2002. [ABSTRACT FROM AUTHOR]

A compact wideband dual-polarized microstrip antenna element for phased-array antennas is presented. The feeding lines are distributed on two layers, which facilitate the design of complex antenna arrays. The antenna element has a return loss greater than 10 dB, and an isolation between the input ports over 35 dB from 10.7 to 12.6 GHz. Also, a four-element array is constructed and measured. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 396–398, 2001. [ABSTRACT FROM AUTHOR]

A novel dual-frequency dual-polarized square microstrip patch antenna embedded with a slot is presented. The proposed antenna offers tunability of the frequency ratio between the two frequencies by adjusting the slot dimensions. This configuration also provides a size reduction up to ∼51 and 35% for the two modes as compared to a square microstrip patch antenna. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 395–397, 2000. [ABSTRACT FROM AUTHOR]

Experimental studies on a compact dual-frequency microstrip antenna are presented. This antenna configuration provides an area reduction of 40% compared to a standard rectangular antenna operating at the same frequency without much degradation of the gain. The antenna structure can be modified to achieve the desired ratio between the two resonant frequencies. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 328–330, 2000. [ABSTRACT FROM AUTHOR]