一种具有谐波抑制功能的圆极化天线设计

微波能量传输以及无线通信系统中的天线设计,追求剖面低、质量轻,易与平面电路集成。基于此,设计了一种具有谐波抑制功能的单馈背腔圆极化环缝天线。该天线工作在5.8 GHz,采用导波结构基片集成波导(SIW)抑制表面波,提高了天线增益。SIW通过2排金属孔阵列集成在介质板上,在介质板上蚀刻短路圆环缝隙,辐射电磁波。采用50 Ω微带线到SIW过渡的背馈方式,并在馈线上引入并联枝节,有效抑制了高次谐波,且实现了基于基片集成波导天线的谐波抑制。通过加工测试,天线的轴比为0.67 dB,增益为6.9 dBi,阻抗匹配良好,前后比为22 dB,仿真结果与实测结果吻合良好。     

具有谐波抑制功能的圆极化整流天线设计

设计了一款新型的具有谐波抑制能力的圆极化整流天线。在圆环缝隙天线的中心挖圆形孔,控制天线的谐振频带与抑制高次谐波。在缝隙的内边缘开两个半圆形槽,缩减天线的尺寸并获得圆极化辐射。倍压整流电路有效地提高了整流天线的输出直流电压。仿真结构表明,天线谐振带宽(VSWR＜2)为17.6％,圆极化带宽(AR＜3 dB)达到3.7％。整流电路在0 dBm的输入功率时,能达到59％的整流效率和1.7 V的直流输出电压。该整流天线可作为无源射频识别(Radio Frequency Identification,RFID)标签的整流天线。     

具有谐波抑制功能的双极化缝隙天线

针对微波能量传输领域中接收天线与发射天线发生极化失配时,整流天线接收的能量会急剧下降的问题,设计了一款工作在2.45 GHz具有谐波抑制功能的双极化缝隙接收天线,该接收天线本身发生一定角度旋转时仍可通过双极化的特性接收能量。通过在贴片上开大小合适、结构对称的缝隙,实现天线水平极化和垂直极化;运用缺陷地结构,实现谐波抑制功能。仿真结果显示,在2.45 GHz处,天线的隔离度高于17.6 dB,增益3.9 dBi,阻抗匹配良好,在二次、三次谐波处天线的回波损耗为-0.38 dB和-0.96 dB,仿真结果和实测基本吻合。     

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。     

一种共形宽带圆极化螺旋天线的设计

为满足共形天线低剖面特性的要求,设计并制作了一种低剖面的圆极化阿基米德螺旋天线.天线利用单臂阿基米德螺旋结构实现圆极化辐射,并采用同轴探针馈电.实测结果表明,天线在2～ 11.4 GHlz的频率范围内回波损耗小于-10dB,轴比小于3dB的频率范围为2.5～8.4 GHz.该天线结构简单,工作频带宽,且剖面极低,可作为...     

一种实用新型宽波束圆极化天线

圆极化天线是一种应用非常广泛的天线形式，尤其是在卫星通信和卫星定位设备中，随着这些系统的发展，对天线提出了越来越高的要求，低剖面、宽波束覆盖的圆极化天线越来越受到追捧，本文提出了一种新型宽波束圆极化天线—双臂螺旋天线，该天线3dB 波束宽度可达160°以上，具有结构简单、尺寸小、性能稳定等优点，可以广泛应用于各种军用、民用通信领域。     

一种低剖面宽带二维宽角扫描圆极化阵列天线

针对现有圆极化平面阵列的扫描角受限和三维宽角扫描阵列体积大的问题,设计了一种基于阵因子方向图和单元因子方向图互补的低剖面宽角扫描圆极化阵列天线.该阵列单元采用新型圆极化正交偶极子天线,并由其组成多个圆环子阵,每一子阵内单元的法向均偏离阵列法向一个固定倾角并等间距排布在"涟漪"状金属地板上.这种阵列排布方式使得在主波束扫描至大角度时天线单元因子增益可以补偿阵因子的增益下降.设计的一个64元阵列天线的实测结果表明:在8~9 GHz工作带宽内,且波束扫描覆盖0°~±62°,各阵元的有源驻波比均小于2.1,中心频点扫描增益起伏小于1.71 dB,扫描波束的圆极化轴比小于2 dB.     

具有谐波抑制功能的共面波导轻薄整流天线

为解决对无人机、平流层飞艇等空中移动目标无线输能时机载接收端整流天线质量大,占居飞行器有效载荷多的难题,设计了一种具有谐波抑制功能的共面波导轻薄圆极化整流天线。该整流天线采用集中式整流方式,通过将整流电路直接集成在微带天线接地板上,实现了质量轻,尺寸小,剖面低,易共形的圆极化整流天线。该天线工作在5.8 GHz,采用共面波导耦合馈电,并在馈线上直接加载共面波导谐振结构进行谐波抑制,具有较宽的工作带宽。整流电路采用倍压整流形式,利用贴片电容作为直通滤波器进行直流滤波,电路结构简单。该整流天线结构紧凑,质量仅6.28 g,剖面厚度0.5 mm,最佳整流效率63.84%,测试结果与仿真结果吻合良好,验证了该设计的可行性。     

基于超表面的宽带低剖面圆极化天线设计

设计并制备了一种基于超表面的宽带低剖面圆极化天线。该天线由上下两层构成,下层是传统的线极化缝隙微带天线,上层是由方形切角单元构成的超表面。分析了超表面将线极化波转换成圆极化波的工作原理,并对影响天线圆极化带宽的参数进行了优化。仿真结果表明:加载超表面后,不仅使天线辐射圆极化波,还扩展了天线的阻抗带宽,天线相对阻抗带宽达到17%,3 dB轴比带宽达到7.2%。为了验证设计的有效性,加工、测试了天线实物样品,并与仿真结果进行了对比。实测结果与仿真结果吻合较好,说明该天线具备宽带圆极化特性。最终天线整体尺寸仅为0.4λ×0.4λ×0.03λ,天线的剖面较低,非常有利于与载体共形的应用。     

基于超表面的低剖面宽带圆极化天线

基于超表面设计了一款低剖面、宽带、圆极化天线。天线由改进的Wilkinson功分器馈电实现宽带90°相位差,超表面单元在传统方环形单元上加载箭头结构来增加额外的等效电容,进一步改善了天线带宽和增益性能。仿真和测试结果表明,天线的阻抗带宽为36.7%(2.0 GHz-2.9 GHz),3dB轴比带宽为26.1%(2.0 GHz-2.6 GHz),保持稳定右旋圆极化辐射,峰值增益8dBic,整体天线厚度仅0.05 A。(6mm)。     

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 circularly polarized slot antenna for high gain applications

A coplanar waveguide fed slot antenna for wideband circular polarization is designed and experimentally validated. The rectangular slot is excited using a stepped feed line terminated on a circular disc shaped tuning stub. To obtain circular polarization, inverted L-shaped strips are attached to the ground plane at the opposite corners while a rectangular slit is cut in the circular disc. The combined bandwidth (3-dB axial ratio and 10 dB impedance matching) achieved is 48% (4.35–7.1 GHz) under simulation and 40% (4.75–7.1 GHz) in measurement. The gain of the antenna is next enhanced by the application of a double layered square loop frequency selective surface. The frequency selective surface is used as a reflector placed beneath the antenna at an optimum distance. An improvement of about 4 dB is seen in the measured peak gain over most of the operating band. Experimental results are presented to characterize the antenna and the frequency selective surface and they are found to be in good agreement with the simulated results.     

SIW cavity-backed circularly polarized square ring slot antenna with wide axial-ratio bandwidth

In the proposed work, Substrate Integrated Waveguide (SIW) cavity-backed circularly polarized slot antenna for wideband operation is proposed. A square-ring-slot is etched on the top of the SIW cavity, used for radiation To generate the circularly polarized (CP) wave, the slot is placed slightly offset from the centroid of the cavity. By finely optimizing the antenna dimensions, it exhibits a wide axial-ratio (AR) bandwidth of 789 MHz (7.1%) ranging from 10.64 to 11.45 GHz. Moreover, the radiating slot is excited by an SIW based feed by an inductive window, which lead to a wide impedance matching over 1.74 GHz ranging from 9.92 to 11.67 GHz. Due to the SIW cavity-backing structure, the antenna offers unidirectional radiation patterns while maintaining a low-profile and planar compatibility. To validate the proposed design, the antenna is fabricated and experimentally tested in terms of reflection coefficients, AR, gain, and radiation patterns. The simulated and measured results reveal good mutual agreement. Moreover, the proposed antenna is very useful for wideband applications operating in X-band (8–12 GHz)     

Compact microstrip-fed meander slot antenna for harmonic suppression

A novel compact microstrip-fed meander slot antenna is proposed to achieve suppression of harmonics and miniaturisation of the antenna. To obtain these characteristics, a meander-type slot radiator and U-shaped conductor line connected with the ground plane are applied. The real parts of the measured input impedance at the second- and third-harmonic frequencies are nearly zero. In the measured radiation patterns in E- and H-plane, the second- and third-harmonic suppressions are observed to be approximately less than -30 dB.     

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.     

Development of wideband CPW-fed hexagon-shaped circularly polarized slot antenna for wireless-communications

A hexagonal shaped circularly polarized (CP) wideband slot antenna using multiple stubs has been proposed and investigated. A hexagonal slot is created in the ground plane with tapered sections improving the impedance matching. Two radiators are incorporated in the structure, which is responsible for generating orthogonal degenerate modes; hence, CP radiation is achieved for the proposed antenna. For enhancing the gain of antenna, one radiator is directly connected to feed line and another one embedded in the ground plane. An inverted L-shaped arm is inserted in the slot to enhance and tune the circular polarized behavior. The presented radiator have input reflection coefficient ranges from 5.67 to 8.50 GHz (39.97%) and axial ratio bandwidth (ARBW) of 5.60–8.50 GHz (41.13%). The proposed antenna provides overlapping bandwidths of 5.67–8.50 GHz (39.97%) having average gains of 5.25 dBi within the entire frequency bands. The presented antenna is exceptionally good for the application of mobile and satellite communications.     

Wideband linear and circularly polarized patch antenna using aprinted stepped T-feed

The inherent disadvantage of the narrow bandwidth of microstrip antennas is overcome by a wideband feed mechanism. A square patch excited by a stepped T-feed probe achieved an octave bandwidth (0.98 to 2.1 GHz) with a voltage standing wave ratio of <2. A similar return loss over an octave bandwidth (1.05 to 2.4 GHz) was measured when two orthogonal stepped T-feed probes fed by a log-periodic balun were used to generate circular polarization (CP). For CP, pattern symmetry is shown to occur over 50% of the band, and the CP 3 dB axial-ratio bandwidth is of the order of 30%