Showing papers in "IEEE Antennas and Wireless Propagation Letters in 2009"
TL;DR: The ridge gap waveguide as mentioned in this paper is a metamaterial-based waveguide that can be realized in a narrow gap between two parallel metal plates by using a texture or multilayer structure on one of the surfaces.
Abstract: This letter presents a new metamaterial-based waveguide technology referred to as ridge gap waveguides. The main advantages of the ridge gap waveguides compared to hollow waveguides are that they are planar and much cheaper to manufacture, in particular at high frequencies such as for millimeter and sub- millimeter waves. The latter is due to the fact that there are no mechanical joints across which electric currents must float. The gap waveguides have lower losses than microstrip lines, and they are completely shielded by metal so no additional packaging is needed, in contrast to the severe packaging problems associated with microstrip circuits. The gap waveguides are realized in a narrow gap between two parallel metal plates by using a texture or multilayer structure on one of the surfaces. The waves follow metal ridges in the textured surface. All wave propagation in other directions is prohibited (in cutoff) by realizing a high surface impedance (ideally a perfect magnetic conductor) in the textured surface at both sides of all ridges. Thereby, cavity resonances do not appear either within the band of operation. The present letter introduces the gap waveguide and presents some initial simulated results.
738 citations
TL;DR: In this paper, a tree-like structure on the ground plane is proposed for UWB MIMO/diversity antenna with a size of 35 × 40 mm2 operating at a frequency range of 3.110 GHz.
Abstract: A compact printed ultrawideband (UWB) multiple-input multiple-output (MIMO)/diversity antenna system (of two elements) with a size of 35 × 40 mm2 operating at a frequency range of 3.110.6 GHz is proposed. The wideband isolation can be achieved through a tree-like structure on the ground plane. The effectiveness of the tree-like structure is analyzed. Measured S-parameters show that the isolation is better than -16 dB (-20 dB in most of the band) across the UWB of 3.110.6 GHz. The radiation patterns, gain, and envelope correlation coefficient are also measured. The proposed antenna is suitable for some portable MIMO/diversity applications.
397 citations
TL;DR: In this article, a conformal radio frequency identification (RFID) antenna with a single-walled carbon nanotube (SWCNT) composite was integrated in a chipless RFID node for toxic gas detection.
Abstract: This letter introduces for the first time the integration of a conformal radio frequency identification (RFID) antenna with a single-walled carbon nanotube (SWCNT) composite in a chipless RFID node for toxic gas detection. The electrical performance characterization of the inkjet-printed SWCNT film is also reported for the first time up to 1 GHz. The whole module is realized by inkjet printing on a low-cost paper-based substrate, and the RFID tag is designed for the European UHF RFID band. The electrical conductivity of the SWCNT film changes in the presence of very small quantities of toxic gases like ammonia and nitrogen oxide, resulting in the variation of the backscattered power level, which can be easily detected by the RFID reader to realize reliable wireless toxic gas sensing.
309 citations
TL;DR: In this article, a dual-polarized magneto-electric dipole antenna excited by two-shaped strips is presented, which achieves a common impedance bandwidth of 65.9% (SWR < 2) at both input ports.
Abstract: A novel dual-polarized magneto-electric dipole antenna excited by two -shaped strips is presented. The antenna achieves a common impedance bandwidth of 65.9% (SWR < 2) at both input ports. The antenna has excellent performance in isolation, which is more than 36 dB between the two input ports, and the gain of the antenna is about 9.5 dBi. The radiation pattern and bandwidth over the operating frequency band are very stable.
271 citations
TL;DR: In this paper, a printed monopole antenna for ultrawideband (UWB) applications is proposed, which consists of a square radiating patch with two rectangular slots and a ground plane with inverted T-shaped notch, providing a wide usable fractional bandwidth of more than 120% (3.1212.73 GHz).
Abstract: In this letter, we present a novel printed monopole antenna for ultrawideband (UWB) applications. The proposed antenna consists of a square radiating patch with two rectangular slots and a ground plane with inverted T-shaped notch, which provides a wide usable fractional bandwidth of more than 120% (3.1212.73 GHz). The proposed antenna is simple and small in size. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.
217 citations
TL;DR: This letter presents a new antenna design suitable for cognitive radio communication that consists of two structures incorporated together into the same substrate that is frequency reconfigurable triangular-shaped patch for establishing communication with another RF device.
Abstract: This letter presents a new antenna design suitable for cognitive radio communication. It consists of two structures incorporated together into the same substrate. The first structure is an ultrawideband (UWB) antenna covering the spectrum from 3.1-11 GHz for channel sensing. The second structure is a frequency reconfigurable triangular-shaped patch for establishing communication with another RF device. The antenna reconfigurability is achieved via a rotational motion. A prototype antenna was fabricated and tested in order to validate the suggested method.
210 citations
TL;DR: In this article, a meshed patch antenna is designed and integrated on after-market solar cells, and the antenna has an optical transparency of 93% and the measurements agree well with the design.
Abstract: This letter presents the study of integrating meshed patch antennas directly onto the solar cells of a small satellite to save valuable surface real estate. The cover glass of the solar cell is used as the substrate for the antennas. The integrated patch antennas are designed to have sufficient optical transparency to ensure the proper functionality of the solar cells. A prototype meshed patch antenna is designed and integrated on after-market solar cells. The antenna has an optical transparency of 93%, and the measurements agree well with the design.
202 citations
TL;DR: In this article, a planar antenna using a doubly resonant transmission line metamaterial (TL-MTM) structure is proposed, which is well matched to 50 Omega through an embedded series meandered line.
Abstract: A wideband and compact planar antenna is proposed using a doubly resonant transmission-line metamaterial (TL-MTM) structure. The antenna consists of two TL-MTM arms that resonate at different frequencies. Each arm comprises a microstrip transmission-line loaded with five spiral inductors and is well matched to 50 Omega through an embedded series meandered line. Each arm is designed to work as a single antenna at its own resonant frequency, determined by the loading spiral inductance, where a zero insertion phase occurs. A wideband antenna matching is enabled when these two resonances suitably merge together. A fabricated prototype has dimensions of lambdao/4 times lambdao/7 times lambdao/29, yielding a vertical linear electric field polarization, and provides a 100-MHz bandwidth (-10 dB) with a measured radiation efficiency of 65.8% at 3.30 GHz.
198 citations
TL;DR: In this article, the authors presented the first experimental work on microwave breast cancer imaging using inhomogeneous breast phantoms using a recently designed 31-antenna array, which operates in the full ultrawideband frequency range between 3 and 10 GHz.
Abstract: This letter presents, for the first time, experimental work on microwave breast cancer imaging using inhomogeneous breast phantoms. A recently designed 31-antenna array is used in imaging experiments. The imaging system operates in the full ultrawideband frequency range, between 3 and 10 GHz. To verify imaging performance of our system, new breast phantoms with inhomogeneous interior were developed. For three different breast phantoms presented in this work, the contrast between spherical phantom tumors and surrounding materials ranges from 5:1 to 1.6:1. Our results show that the biggest challenge in radar microwave imaging is the inhomogeneity of the volume being sensed, and not the contrast itself. In addition to experimental results, we also present the new image formation algorithm, which is a modified version of the delay-and-sum (DAS) algorithm. The new algorithm makes use of a new weighting factor, the coherence factor. The new algorithm is effective in reducing clutter, providing better images. For the most demanding imaging example presented herein, the new algorithm improves the peak clutter-to-target energy ratio by 3.1 dB.
174 citations
TL;DR: In this article, a spade-shaped ultrawideband (UWB) printed planar monopole antenna with triple band-notched characteristics is proposed by employing a hook-shaped defected ground structure (DGS) in each side of the ground plane, embedding an Omega-shaped slot on the radiating patch as well as adding a semi-octagon-shaped resonant ring on the back side of antenna, triple notched frequency bands are achieved.
Abstract: A novel spade-shaped ultrawideband (UWB) printed planar monopole antenna with triple band-notched characteristics is proposed. By employing a hook-shaped defected ground structure (DGS) in each side of the ground plane, embedding an Omega-shaped slot on the radiating patch as well as adding a semi-octagon-shaped resonant ring on the back side of the antenna, triple notched frequency bands are achieved. The proposed antenna has been successfully simulated, fabricated, and measured. Effects of the key parameters on the frequency ranges of the notched bands are also investigated. The measured impedance bandwidth defined by VS WR < 2 of 10.1 GHz (2.9-13 GHz), with the triple notched bands of 3.3-3.9, 5.2-5.35, and 5.8-6.0 GHz, is obtained. Measured group delay and transmission characteristics indicate that the antenna has good transient response. Furthermore, the proposed antenna shows the merit of insensitivity to both finite ground size and fabrication tolerances.
168 citations
TL;DR: In this paper, a single-layer substrate frequency selective surface (FSS) made of miniaturized elements is proposed, with two controllable passbands obtained, each FSS element consists of a loop wire on the top metal layer and its complementary pattern etched at the bottom one, which provides two transmission poles separated by a transmission zero.
Abstract: A single-layer substrate frequency selective surface (FSS) made of miniaturized elements is proposed, with two controllable passbands obtained. Each FSS element consists of a loop wire on the top metal layer and its complementary pattern etched at the bottom one, which provides two transmission poles separated by a transmission zero. An equivalent circuit model is given for predicting the characteristics of the designed FSS, and a good agreement between the simulated and measured transmission coefficients is obtained. Furthermore, the cases of oblique wave incidence and cascading FSSs are also measured and examined.
TL;DR: This letter investigates a new reconfigurable antenna technique based on the rotation of a slot that remains unchanged for different slot positions and investigates the process for automatic rotation and control of the slot using graph models.
Abstract: This letter investigates a new reconfigurable antenna technique based on the rotation of a slot. The surface currents are redistributed for each slot position. The antenna is simulated, fabricated, and tested. The return loss frequency tuning matches the simulated data. The antenna radiation pattern remains unchanged for different slot positions. Finally, the process for automatic rotation and control of the slot is investigated using graph models.
TL;DR: In this paper, a printed monopole antenna (PMA) for ultrawideband (UWB) applications with variable frequency band-notch characteristic is presented, which consists of a stepped square radiating patch with two U-shaped slots and a notched ground plane with a T-shaped sleeve that provides a wide usable fractional bandwidth of more than 140%.
Abstract: In this letter, a novel printed monopole antenna (PMA) for ultrawideband (UWB) applications with variable frequency band-notch characteristic is presented. The proposed antenna consists of a stepped square radiating patch with two U-shaped slots and a notched ground plane with a T-shaped sleeve that provides a wide usable fractional bandwidth of more than 140% (2.8516.73 GHz). By cutting two modified U-shaped slots with variable dimensions on the radiating patch, frequency band-stop performance is generated, and we can control its characteristics such as band-notch frequency and its bandwidth. The designed antenna has a small size of 12 times 19 mm2 while showing the band rejection performance in the frequency band of 5.02-5.97 GHz.
TL;DR: In this paper, a high-efficient and high-gain aperture coupled patch antenna with superstrate at 60 GHz was studied and presented, and it was shown that adding superstrate will result in a significant effect on the antenna performances, and the size of the superstrate is critical for the optimum performance.
Abstract: A high-efficient and high-gain aperture coupled patch antenna with superstrate at 60 GHz is studied and presented. It is noted that adding superstrate will result in a significant effect on the antenna performances, and the size of the superstrate is critical for the optimum performance. The maximum measured gain of a single antenna with superstrate is 14.6 dBi, which is higher than that of a classical 2 x 2 array. It is found that the gain measured of a single antenna with superstrate increases nearly 9 dB at 60 GHz over its basic patch antenna. This superstrate antenna gives a very high estimated efficiency of 76%. The 2:1 measured VSWR bandwidth with superstrate is 6.8%. The radiation patterns are found to be broadside all over the frequency band. Also, this letter explains a comparison to another source of parasitic patch superstrate antenna with normal microstrip coupling. It is found that aperture coupling is better for high-gain antenna applications.
TL;DR: In this article, the relation between different parameters that characterize the reverberation chamber as a channel emulator for over-the-air (OTA) testing of wireless devices and components is investigated.
Abstract: This letter finds the relation between different parameters that characterize the reverberation chamber as a channel emulator for over-the-air (OTA) testing of wireless devices and components. It is shown experimentally for the first time that the coherence bandwidth is proportional to the average mode bandwidth of the chamber. Both coherence bandwidth and average mode bandwidth increase when the chamber is loaded with absorbing objects, and thereby, the reverberation chamber can be controlled to emulate many different real-life environments. The relationship between RMS delay spread and coherence bandwidth are found from the measured channel response and are equal to the theoretical relation for isotropic multipath environments, being within previously published fundamental limits.
TL;DR: In this paper, a dual integral-equation formulation of the source reconstruction problem on arbitrary three-dimensional (3D) surfaces based on integral equations is presented. But the authors do not consider the problem of source reconstruction on arbitrary 3D surfaces, and they use boundary integral field identities to enforce that the unknown currents are Maxwellian on the reconstruction surface.
Abstract: This paper presents a novel formulation of the source reconstruction problem on arbitrary three-dimensional (3-D) surfaces based on integral equations. Rigorous boundary integral field identities are employed to enforce that the two unknown currents are Maxwellian on the reconstruction surface; this leads to a dual integral-equation formulation, in contrast to the single-equation formulation found in literature. Numerical tests against reference currents allow a quantitative assessment of the improvements in accuracy afforded by the novel formulation, with important benefits in diagnostic applications.
TL;DR: In this article, a planar multiple-input-multiple-output (MIMO) antenna system of four elements with similar radiation characteristics is proposed for the whole 2.4 GHz WLAN band.
Abstract: A compact planar multiple-input-multiple-output (MIMO) antenna system of four elements with similar radiation characteristics is proposed for the whole 2.4-GHz WLAN band. It consists of two proximity-coupled fed microstrip square ring patch antennas and two lambda/4 microstrip slot antennas of the same linear polarization. These two types of antennas are printed on different sides of the substrate to reduce mutual coupling. With a novel isolation structure etched on the ground plane of the FR4 substrate, high port isolation (below -25 dB) and good MIMO performance are achieved. The overall lateral size of the MIMO system is only 0.64lambda times 0.48A, and good impedance matching (S11 < 10 dB) is achieved across the operating band for all the antenna elements. Full spherical radiation patterns are measured for the MIMO system, showing similar radiation characteristics, and the gains are above 2.3 dB across the operating band.
TL;DR: In this article, a co-designed antenna-filter is presented, which is composed of a microstrip patch antenna and a hairpin filter, both of which share the same ground plane to reduce the size.
Abstract: In this letter, a co-designed antenna-filter is presented. The antenna-filter is composed of a microstrip patch antenna and a hairpin filter, both of which share the same ground plane to reduce the size. Instead of using the traditional 50-Omega interfaces, the impedance between the filter and antenna is optimized to improve the performance. The simulated and measured results have demonstrated that co-designed antenna-filter has a better bandwidth (4.7%, 4.064.26 GHz) and a larger gain (4.3 dBi) than the traditional version with 50-Omega interfaces impedance.
TL;DR: In this paper, a dual-element antenna at 710 MHz for personal wireless communication (LTE) standard applications is proposed. But the antenna elements are printed on FR-4 substrate and are located at the top edge of the ground plane measuring 50 × 87 mm2.
Abstract: A compact dual-element antenna has been designed at 710 MHz for newly emerging long-term evolution (LTE) personal wireless communication standard applications. The proposed antenna consists of two printed meander-line monopoles with edge-to-edge separation of nearly ?/45. The antenna elements are printed on FR-4 substrate and are located at the top edge of the ground plane measuring 50 × 87 mm2. An LC-components-based branchline hybrid coupler is used to decouple the antenna elements. The prototype antenna has been evaluated through the scattering parameters, radiation patterns, envelope cross correlation, and the channel capacity measurements. Isolation between the ports is better than 35 dB with matched ports at 710 MHz. The antenna offers reasonable multiple-input-multiple-output (MIMO) performances that make it suitable for LTE-standardized mobile phones.
TL;DR: In this paper, a small-sized, low-profile, and planar integrated Bluetooth and ultrawideband (UWB) antenna is presented, which exhibits a dual-band operation covering 2400-2484 MHz (Bluetooth) and 3100-10600 MHz frequency bands.
Abstract: A small-sized, low-profile, and planar integrated Bluetooth and ultrawideband (UWB) antenna is presented. The antenna exhibits a dual-band operation covering 2400-2484 MHz (Bluetooth) and 3100-10600 MHz (UWB) frequency bands. It is fed by a microstrip line and built on a FR-4 substrate with 42times46 mm2 surface area. The impedance, radiation, phase linearity, and impulse response properties of the antenna are studied both theoretically and experimentally. The calculated and measured results agree well. The antenna shows acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands. The average group delay is approximately 0.2 ns across UWB frequencies. The impulse response is very good, with some level of ringing observed.
TL;DR: In this paper, a planar zero-index metamaterial (ZIM) was used to obtain a high-directivity microstrip patch antenna (MPA) with an effective permittivity that approaches zero at 8.75 GHz.
Abstract: In this letter, a novel high-directivity microstrip patch antenna (MPA) based on planar zero-index metamaterials is presented. An averaging effect over the metamaterial structure yields an effective permittivity that approaches zero at 8.75 GHz, which results in a metamaterial with zero index of refraction. Both the simulation and experimental results show that the directivity of the antenna is effectively enhanced based on the zero refraction characteristics of the metamaterial.
TL;DR: In this paper, a novel engineered magnetic superstrate designed to enhance the gain and efficiency of a microstrip patch antenna without any substantial increase in the profile of the whole structure (the antenna with the superstrate).
Abstract: This letter presents a novel engineered magnetic superstrate designed to enhance the gain and efficiency of a microstrip patch antenna without any substantial increase in the profile of the whole structure (the antenna with the superstrate). The modified split ring resonator (MSRR) inclusions are used in the design of the engineered magnetic superstrate. Numerical full-wave simulations as well as analytical models are used to analyze the entire radiating system. Considering as an example a microstrip antenna operating within the UMTS band, the broadside gain of the antenna was improved by 3.4 dB and the efficiency was improved by 17% when using the engineered superstrate. The total height of the proposed structure, antenna with superstrate, is lambda0/7, where lambda0 is the free-space wavelength at the resonance frequency of the antenna.
TL;DR: In this paper, a symmetric dual-layer frequency-selective surfaces (FSSs) radome is integrated on the radiation surface of a planar slotted waveguide antenna.
Abstract: This letter presents a new possible solution for realizing a symmetric dual-layer frequency-selective surfaces (FSSs) radome that is integrated on the radiation surface of a planar slotted waveguide antenna. The use of FSS radome results in a significant performance improvement of the planar slotted antenna. Experimental results are presented and compared to simulations by an electromagnetic simulator, and they demonstrated that the radar cross section (RCS) properties of the antenna covered by FSS radome can be significantly improved. Moreover, the presented FSS radome also exhibits good transmission characteristics such as wide bandwidth at the operating frequency 9.5 GHz.
TL;DR: In this paper, a novel bionic ultrawideband (UWB) antenna is proposed by use of a model of insect tentacle, and its radiation characteristics are simulated and experimentally verified.
Abstract: Bionics principle is applied to antenna radar cross section (RCS) reduction in this letter for the first time. To authenticate the method, a novel bionic ultrawideband (UWB) antenna is proposed by use of a model of insect tentacle. Its UWB-related radiation characteristics are simulated and experimentally verified. Monostatic RCS of an insect tentacle antenna (ITA) terminated with three different loads are studied and compared with that of a common printed circular-disc monopole antenna (PCDMA). The results show that compared to the reference antenna, the novel bionic antenna has lower RCS and favorable radiation performances. Hence, applying bionics principle to antenna RCS reduction is feasible, which will serve as a good candidate for the future design of antennas with a requirement of RCS control.
TL;DR: In this paper, a microstrip-fed antipodal tapered-slot antenna with ultrawideband performance and miniaturized dimensions is presented, where the antenna's structure is modifies to establish a direct connection between the microstrip feeder and the radiator.
Abstract: A method to design a microstrip-fed antipodal tapered-slot antenna, which has ultrawideband (UWB) performance and miniaturized dimensions, is presented. The proposed method modifies the antenna's structure to establish a direct connection between the microstrip feeder and the radiator. That modification, which removes the need to use any transitions and/or baluns in the feeding structure, is the first step in the proposed miniaturization. In the second step of miniaturization, the radiator and ground plane are corrugated to enable further reduction in the antenna's size without jeopardizing its performance. The simulated and measured results confirm the benefits of the adopted method in reducing the surface area of the antenna, while maintaining the ultrawideband performance.
TL;DR: In this paper, the weighted L2-norm total variation multiplicative regularized Gauss-Newton inversion method was used for microwave biomedical imaging, which automatically adjusts the regularization weight and provides edge-preserving characteristics.
Abstract: The weighted L2-norm total variation multiplicative regularized Gauss-Newton inversion method, recently developed for inversion of low-frequency deep electromagnetic geophysical measurements, is used for microwave biomedical imaging. This inversion algorithm automatically adjusts the regularization weight and provides edge-preserving characteristics. The accuracy of this method is demonstrated by inverting experimental data of a human forearm and synthetic data taken from brain and breast models, both assuming two-dimensional (2D) transverse magnetic illumination.
TL;DR: In this paper, a printed monopole antenna is proposed which uses negativerefractive-index transmission-line (NRI-TL) metamaterial loading in order to achieve a broadband dual-mode operation.
Abstract: A printed monopole antenna is proposed which uses negative-refractive-index transmission-line (NRI-TL) metamaterial loading in order to achieve a broadband dual-mode operation. The metamaterial-loaded monopole supports a predominately even-mode current at 5.5 GHz, which allows the antenna to be modeled as a short folded monopole. Around 3.55 GHz, the metamaterial-loaded monopole acts as a balun for the ground plane currents, therefore rendering the entire top edge of the ground plane as the main radiating element. This in turn radiates a dipolar mode that is orthogonal to the folded-monopole mode at 5.5 GHz. By virtue of the orthogonality between the two radiating modes, the metamaterial antenna exhibits a return-loss characteristic with a dual resonance, and therefore a very wide measured impedance bandwidth of 4.06 GHz. The total size of the antenna is only 22 times 30 mm, and the measured efficiency is on the order of 90% at both 3.55 and 5.5 GHz.
TL;DR: In this paper, a coplanar waveguide (CPW)-fed monopole antenna is proposed, which is composed of a rectangular monopole patch notched at the bottom, a T-shaped CPW ground in the notch, and a tapered CWS ground out of the notch.
Abstract: A coplanar waveguide (CPW)-fed monopole antenna is proposed, which is composed of a rectangular monopole patch notched at the bottom, a T-shaped CPW ground in the notch, and a tapered CPW ground out of the notch. The simulated and experimental results show that the antenna achieves a fractional impedance bandwidth of 164% for S11 ? -10 dB, which is about 2.3 times of the conventional one. The parametric studies and measured radiation characteristics are presented. The results show that the antenna exhibits good characteristics and is suitable for portable mobile ultrawideband (UWB) applications.
TL;DR: This letter will present the explicit expression for defining the bandwidth of a HIS, and it will show that the reduction of the FSS inductance results in the best choice for achieving wide operating bandwidth in correspondence with a given frequency.
Abstract: In this letter, the bandwidth of high-impedance surfaces (HISs) is discussed by an equivalent circuit approach. Even if these surfaces have been employed for almost 10 years, it is sometimes unclear how to choose the shape of the frequency selective surface (FSS) on the top of the grounded slab in order to achieve the largest possible bandwidth. Here, we will show that the conventional approach describing the HIS as a parallel connection between the inductance given by the grounded dielectric substrate and the capacitance of the FSS may induce inaccurate results in the determination of the operating bandwidth of the structure. Indeed, in order to derive a more complete model and to provide a more accurate estimate of the operating bandwidth, it is also necessary to introduce the series inductance of the FSS. We will present the explicit expression for defining the bandwidth of a HIS, and we will show that the reduction of the FSS inductance results in the best choice for achieving wide operating bandwidth in correspondence with a given frequency.
TL;DR: A top-wall substrate integrated waveguide (SIW) slot radiator for generating circular polarized (CP) field is proposed and characterized in this article, where the reflection of the slot radiator is extremely weak and simplifies the linear traveling wave array design.
Abstract: A top-wall substrate integrated waveguide (SIW) slot radiator for generating circular polarized (CP) field is proposed and characterized in this letter The reflection of the slot radiator is extremely weak, which simplifies the linear traveling wave array design Based on such a structure, a 16-element CP SIW traveling wave antenna array is designed, fabricated, and measured at 16 GHz A -23 dB side lobe level (SLL) with an axial ratio (AR) of 195 dB is experimentally achieved The size of the proposed SIW CP linear array antenna is 285 mm times 22 mm The measured gain is 189 dB, and the usable bandwidth is 25%