一种高效率圆极化背腔天线阵的设计

设计了一种新型单臂螺旋边馈阶梯喇叭圆极化背腔天线,天线单元由阶梯喇叭、单臂螺旋及圆形背腔组成.单臂螺旋采用准空气同轴线激励,给出了天线单元的轴比、驻波、方向图宽频带特性.提出单元旋转反相馈电方法改善了天线子阵轴比和极化隔离,同时解决了馈电空间狭小的难题.对阵列进行了加工测试,测试与仿真结果吻合.结果显示,天线增益、驻波带宽、轴比带宽和方向图性能优良,此种天线具有很好的工程应用前景.     

Broadband circularly polarized CPW-fed slot antenna array for millimeter wave application

A broadband and circularly polarized 1×4 linear antenna array composed of CPW-fed slot elements for millimeter wave application is discussed. Through a special short-circuiting stub perturbation method, the circular ring slot element achieves circular polarization and a broad bandwidth. Through a parallel feeding network, the array achieves a broad impedance bandwidth of 19% with VSWR?2 and CP bandwidth of 18.4% with AR?3 dB and has a peak gain of about 6.8 dB.     

低剖面宽带圆极化天线阵列

基于双馈双线极化微带天线,结合威尔金森功分器、T形结功分器及顺序旋转馈电的优点,设计了一种新型低剖面宽带圆极化2×2天线阵列。把辐射贴片和馈电网络集成在同一介质层,有效地利用了介质空间,降低了天线的剖面,增加了天线的带宽。4个天线单元顺序旋转90°,利用一分四T形结功分器给4个单元等幅、相位依次相差90°馈电。根据Ansoft''s HFSS仿真结果,制作了样机。样机实测结果和仿真结果吻合。实测结果表明,该天线阵驻波带宽可以达到27.78%,3-dB轴比带宽可以达到52%,最大增益为14.19 dB。     

宽角扫描的圆极化相控线阵

设计了一款宽波束的圆极化天线单元以及1×4的天线阵列，实现了一维的宽角圆极化扫描.天线单元由单层的辐射贴片和介质基片集成波导（substrate integrated waveguide，SIW）背腔构成，通过在辐射贴片上切角微扰和开U型槽实现右旋圆极化，并利用SIW背腔缝隙展宽波束.同时利用SIW背腔减小阵列单元间的互耦，实现宽角圆极化扫描.仿真与测试结果表明，天线阵列实现了扫描角为-53°~57°，3 dB波束宽度覆盖范围为-76°~79°，在主波束扫描覆盖范围内轴比（axial ratio，AR）均小于3 dB，且在扫描范围内增益变化平稳，可实现良好的宽角范围的圆极化扫描特性.     

宽带宽波束圆极化微带八木天线

提出了一种具有两级双贴片引向器结构的双馈圆极化微带八木天线.通过移除部分接地板结构,有效地增大了天线在端射前向的圆极化增益和波束宽度.等幅异相的同轴双馈模式使得该天线具有较宽的工作频带.数值仿真与实验结果表明:该天线同时满足驻波比R vsw≤1.5及端射方向轴比RA≤3 dB的相对带宽为11％.天线在俯仰面仰角0°至80°的范围内具有良好的圆极化辐射特性,方位面主极化半功率波瓣宽度达到88°,同时具有较高的辐射前后比.良好的工作特性表明此天线可作为机载或弹载通信的备选天线.     

宽带高增益圆极化微带-喇叭组合天线

研究了一种具有良好工作性能的微带-喇叭组合右旋圆极化天线,首先设计了一种双层宽带圆极化微带天线结构,同时满足电压驻波比(VSWR)≤2,轴比(AR)≤4 dB的频带宽度(Bw)≥24%,主极化增益大于9 dBi;通过引入角锥喇叭结构,在工作频带内将天线增益提高到12 dBi以上,同时不影响原天线的其他性能。为更好了解微带-喇叭组合右旋圆极化天线的性能,并快速而准确地设计该天线结构,对天线主要几何参数进行了适当分析和研究。     

Equally spaced monopole-notch array antenna for circularly polarized wave

Experimental results of a circularly polarized antenna composed of two pairs of monopole-notch arrays arranged orthogonally on a conical conducting plate are described. This antenna can be designed by a simple design procedure, and it provides excellent performance characteristics as a broad-band circularly polarized antenna.     

Gain improvement of circularly polarized array antenna usinglinearly polarized elements

A novel gain improvement method for a circularly polarized array antenna consisting of linearly polarized elements is proposed. It is verified that the gain of a circularly polarized array antenna can be increased by adjusting the array arrangement of the individual linearly polarized elements. The gain of a multiring array antenna consisting of the above mentioned circular array can also be increased by properly combining the directions of the linear polarization of the individual circular arrays. The gain improvement of the single-circular array antenna and the two-ring array antenna using the proposed method are verified by the measured results     

A Ka-band circularly polarized high-gain microstrip array antenna

In this article, the development of a circularly polarized microstrip array with 28 dBic of gain at 32 GHz is presented. Two primary objectives of this development are minimizing the microstrip array's insertion loss and maintaining a reasonable frequency bandwidth (3%). The parallel/series feed technique for the array's power distribution circuit and the sequential rotation method for the element arrangement are employed to meet these objectives     

Broadband circularly polarised high efficiency active antenna

A broadband circularly polarised (CP) high efficiency active antenna is presented, where the antenna is integrated directly with a high efficiency class-E power amplifier (PA). The printed antenna is employed not only as a broadband CP radiator but also as a harmonics-termination load network for the class-E PA. Measured results demonstrate broadband CP radiation and high efficiency.     

Broadband circularly polarized rectangular loop antenna with impedance matching

A broadband circularly polarized rectangular loop antenna is developed. The broadband performance is achieved by adding a pair of parasitic loops inside the rectangular loop. Good impedance matching is obtained by introducing a broadband balun. The proposed rectangular loop has a bandwidth of 46% for axial ratio/spl les/2dB and 50% for VSWR/spl les/2 with a gain of around 8dBi.     

Ka频段双圆极化相控阵天线设计

设计了一个8×8的Ka频段双圆极化相控阵天线。该天线单元采用正交缝隙耦合馈电的多层贴片微带天线,并由一个小型化宽带3 d B枝节电桥实现双圆极化。为提高天线圆极化性能,依次旋转天线单元,形成2×2双圆极化天线子阵。以天线子阵为基础,扩展成8×8相控阵天线。HFSS仿真结果表明,天线在方位360°俯仰±60°范围内进行双圆极化扫描,轴比小于3 d B,且轴比带宽达30%。该研究结果可应用于卫星通信的双圆极化相控阵天线的设计。     

A circularly polarized conical beam spherical slot array antenna

This paper proposes a circularly polarized conical beam spherical slot array antenna which is suitable for a low elevation angle land mobile satellite communication subscriber. The structure of this antenna type is very simple to fabricate; i.e. a ring of perpendicular slot pairs is cut on an outer surface of a concentric conducting spherical cavity. From the assumption of weak coupling of the slots from the cavity, the conical beam pattern can be obtained. Experimental results that verify the conical beam radiation are in good agreement with the design.     

A crank-line array antenna radiating a circularly polarized wave

An array antenna composed of crank-line elements is investigated on the basis of the element current distributions determined by the method of moments. A technique of gradually increasing the antenna height above the ground plane is adopted to enhance the gain. It is found both numerically and experimentally that a gain of approximately 30 dB is obtained with an axial ratio of less than 3 dB over a frequency bandwidth of 2.5%     

Dual-band circularly polarized equilateral triangular-patch array antenna for mobile satellite communications

The Japan Aerospace Exploration Agency will launch the Engineering Test Satellite VIII (ETS-VIII) in 2006 to support the next generation of mobile satellite communications covering the area of Japan (beam coverage El=38/spl deg/ to 58/spl deg/). In this paper, a satellite-tracking left-handed circularly polarized triangular-patch array antenna is developed for ground applications. The targeted minimum gain of the antenna is set to 5 dBic at the central elevation angle (El=48/spl deg/), in the Tokyo area, for applications using data transfer of around a hundred kbps. The antenna is composed of three equilateral triangular patches for both reception and transmission units operating at 2.50 and 2.65 GHz frequency bands, respectively. The antenna was simulated by method of moments (MoM) analysis, and measurement of the fabricated antenna was performed to confirm the simulation results. The measurement results show that the frequency characteristics and the 5-dBic gain coverage in the conical-cut plane of the fabricated antenna satisfy the specifications for ETS-VIII. A prototype of the proposed antenna system is employed in outdoor experiments using a pseudosatellite and shows good performance from El=38/spl deg/ to 58/spl deg/.     

Low-cost, high-efficiency quasi-planar array of waveguide-fed circularly polarized microstrip antennas

A low-cost quasiplanar Ku-band array of circularly polarized microstrip antennas benefiting from a low-loss waveguide feed network is demonstrated (patent pending). The 32 elements of the array which are arranged in a 2-by-16 configuration are subdivided into four two-by-four subarrays. To maintain feed losses and thus the overall noise temperature at a minimum, the subarrays are excited using a one-by-four corporate feed network of hollow metallic waveguides. This network is composed of E-plane components such as Tee-junctions and bends and is manufactured out of only two metallic pieces that accommodate the feed network in the form of milled grooves. Because of insensitivity of the exploited E-plane components to air gaps or slight misalignments, the pieces are secured together with only four screws without welding, braising, or conducting adhesives. Owing to a low-loss foam substrate, the array elements show high circular polarization gain of 9 dBic and wide relative bandwidth of 4%. To achieve circular polarization, use is made of circular patches with two nearly perpendicular perturbations. Using sequential rotation of the elements along with quadrature phase shifting, the axial ratio of the array is reduced to 1 dB over 4% of bandwidth. The measured circular polarization gain of the array amounts to 23 dBic with an aperture efficiency of 63% in the Ku-band of frequencies. The achieved efficiency, which is higher than the reported efficiency for comparable planar arrays with microstrip feed networks, can be credited to the low losses of only 0.2 dB in its waveguide corporate feed. The paper also presents measurement results for an arrangement of two inclined single arrays mounted in parallel. This configuration which has a measured circular polarization gain of 25.7 dBic with an axial ratio of 1 dB is desirable for mobile low-profile antenna systems.     

一种新型布局的圆极化微带天线阵优化设计

提出了一款高增益低副瓣新型圆极化微带天线阵。单元天线采用叠层切角圆极化微带结构,通过八边形边界布局和顺序旋转交叠组阵技术,实现了天线阵方向性图的对称性和圆极化辐射性能的最优化;馈电网络采用威尔金森功分器和最大平坦式阻抗变换器实现不等功分宽带阻抗匹配,通过改进馈电方向寻求对称结构,简化了馈电网络的设计。制作了天线阵实物并进行了测量。测试结果表明:天线在3.2~4.6 GHz频段内S₁₁<-10 dB,阻抗相对带宽36%;在3.8~4.5 GHz频段内顶点轴比小于3 dB,圆极化相对带宽17%;在4~4.4 GHz频段内天线增益均在15 dB以上,最高增益达17 dB。     

一种四单元圆极化微带天线阵的研制

本文设计了一种新颖的四单元圆极化微带天线阵。通过去掉单元贴片周围的介质,使天线阵的重量减少了54%。文中采用电磁仿真软件HFSS10进行优化与仿真,讨论了阵元间距对天线阵的增益、半功率波束宽度、旁瓣电平以及后瓣电平的影响。最后加工制作了相应的微带天线阵,测试结果与仿真吻合较好。     

Ku波段宽角扫描圆极化微带阵列天线设计

提出了一种三馈电圆极化微带天线。天线馈电网络采用一分三功分馈电,实现微带贴片天线的圆极化辐射,增加方向图的旋转对称性。用该天线作为阵列单元,采用顺序旋转布阵技术组成一个3×4阵列,有效地改善了阵列天线的增益扫描特性。研究了该阵列天线波束扫描时的辐射特性和极化特性。仿真结果表明:阵列天线在中心工作频率处能实现俯仰60°的扫描,在扫描范围内增益大于11.9 d Bi,轴比小于2 d B。     

A broadband circularly polarized cavity-backed Archimedean spiral array antenna for C-band applications

In this letter, a new configuration of sequentially rotated circularly polarized (CP) array antenna with a modified gain is investigated. In order to realize the presented antenna, four Archimedean spiral radiators are applied on a substrate, backed by a circularly slotted ground plane. Also a combination of 180° rat-race coupler and 90° branch-line couplers prepare the employed feeding network in this study. Furthermore, cavity-backed structure is utilized to enhance the antenna gain and achieve a directional radiation pattern over the operating frequency band. This configuration also extends the return loss (RL) and the axial ratio (AR) bandwidths, simultaneously. According to the experimental results, the 2 × 2 CP array antenna has RL bandwidth of 64.28%, AR bandwidth of 54.28%, and peak gain of 10.84 dBic. The close correspondence between the measured and the simulated results validates the proposed design.