Design, development, and testing of X-band amplifying reflectarrays

The design and development of two X-band amplifying reflectarrays is presented. The arrays use dual-polarized aperture coupled patch antennas with FET transistors and phasing circuits to amplify a microwave signal and to radiate it in a chosen direction. Two cases are considered, one when a reflectarray converts a spherical wave due to a feed horn into a plane wave radiated into a boresight direction, and the other when the reflectarray converts a spherical wave due to a dual-polarized four-element feed array into a co-focal spherical wave. This amplified signal is received in an orthogonal port of the feed array so that the entire structure acts as a spatial power combiner. The two amplifying arrays are tested in the near-field zone for phase distribution over their apertures to achieve the required beam formation. Alternatively, their radiation patterns or gains are investigated.     

Dual-polarized slot-coupled patch antennas on Duroid with teflonlenses for 76.5-GHz automotive radar systems

A dual-polarized 76.5-GHz microstrip patch and teflon lens antenna system was designed, constructed, and tested. A receiver (RX) array of three dual-polarized microstrip patches was coupled through a 10-cm-diameter lens to produce radiation patterns with 3° beamwidths and beam crossovers of -3 dB. The transmitter (TX) consisted of a single dual-polarized microstrip patch coupled through a 2.5-cm-diameter lens to produce a 10° beamwidth. Slot-coupled patches were used to isolate the microstrip feed circuit from the radiating elements. The antennas and feeds were fabricated on commercially available 5880 Duriod substrates. Cross-polarization levels were less than -20 dB and were typically less than -30 dB over the entire beam at the design frequency. First sidelobe levels were no greater than -15 dB and were typically closer to -20 dB. Stepped and unstepped versions of the 10-cm-diameter receive lens were designed and fabricated. Antenna system sidelobes levels were lower with the stepped lens while the cross-polarization levels were comparable     

并行角馈双极化微带天线阵的分析与设计

本文提出利用双端口的并行角馈实现双极化天线,并设计了一种新的双极化馈线网络。综合运用了多端口网络模型、腔模理论、分片法和补片法,给出了各天线单元和双极化馈线网络的理论分析方法。实际设计了一副6GHz频段的单层共面的四元天线阵,实测的双端口隔离度达-50dB,其性能明显优越于通常的单层双极化微带天线阵列。     

Multiple-polarization microstrip reflectarray antenna with highefficiency and low cross-polarization

This paper presents the study and prototype demonstration of the concepts of antenna focusing, cross-polarization reduction, and multiple-polarization capability of a planar microstrip reflectarray antenna. A square patch with two equal microstrip delay lines connected to its two orthogonal feeding points is used as the antenna element of the planar reflectarray. The length of the delay lines, which varies from patch to patch, is schematically designed to focus the plane wave to the feed point. The measured overall efficiency of the prototype antenna is above 50% in the normal operating band, and in some frequency ranges the efficiency has reached 70%. The experimental patterns show that the measured cross polarization due to special arrangement of the delay lines is quite low at the direction of the main beam. X-polarization and Y-polarization measured data show that the antenna is suitable for multiple-polarization applications (dual linear and dual circular). Surprisingly, the antenna has achieved approximately greater than 7% of gain bandwidth (-3 dB gain drop). These results demonstrate the feasibility of such an antenna for radar and communication system applications     

Design of millimeter wave microstrip reflectarrays

This paper discusses the theoretical modeling and practical design of millimeter wave reflectarrays using microstrip patch elements of variable size. A full-wave treatment of plane wave reflection from a uniform infinite array of microstrip patches is described and used to generate the required patch-design data and to calculate the radiation patterns of the reflectarray. The critical parameters of millimeter wave reflectarray design, such as aperture efficiency, phase errors, losses, and bandwidth are also discussed. Several reflectarray feeding techniques are described, and measurements from four reflectarray design examples at 28 and 77 GHz are presented     

基于时域调制反射阵列的波束赋形技术

传统的反射阵利用相控器件与微带线实现波束赋形。为了降低相控成本与系统复杂度,提出基于时域调制阵列波束赋形技术。时域调制反射阵列是一种基于简单可重构反射单元的反射阵,它利用控制可重构反射单元的开与关,达到控制阵列输出,实现旁瓣抑制、波束赋形等功能。通过理论推导及仿真,结果表明,时域调制反射阵可以在不采用传统阵列中的相控器件及馈电网络的前提下,采用最小方差无失真响应波束赋形方法与时间调制法,生成理想的方向图,实现波束赋形功能。此特性将有利于推广波束赋形技术在毫米波频段反射阵的应用。     

Ka-band reflectarray using ring elements

A simple ring structure to realise a Ka-band circularly polarised microstrip reflectarray is presented. With rotation techniques employed to focus the reflected wave at a focal point, a 0.5 m right-hand circularly polarised microstrip reflectarray is developed and tested at 31.75 GHz resulting in 50% aperture efficiency. The cross-polarisation levels measured are 40.7 dB down at broadside, showing the validity of the structure.     

共口径三波段双极化合成孔径雷达天线阵的设计

介绍了应用于合成孔径雷达(SAR)的一种共口径三波段双极化(TBDP)天线阵的设计。该TBDP天线阵工作于X、S和L波段,频率比为8∶2.8∶1.它由L/S、L/X双波段双极化(DBDP)子阵和一副L波段双极化(DP)子阵组合而成。天线各波段实测的阻抗带宽和方向图都与仿真结果吻合良好。实测的L、S和X波段|S11|≤10dB带宽分别达到13.4%、14.8%和16.8%,各波段带内阵列隔离度均优于37dB.天线实测方向图表明:各波段的主瓣内交叉极化电平低于-30dB,S和X波段扫描能力均优于±25°.该设计方法可以推广应用于实现更多波段的共用口径天线阵。     

A C/ka dual frequency dual Layer circularly polarized reflectarray antenna with microstrip ring elements

This paper reports a dual frequency dual layer circularly polarized reflectarray operating in the C and Ka bands. A 0.5-m right-hand circularly polarized planar reflectarray antenna is designed using microstrip ring elements of variable rotations to achieve a cophasal beam at broadside. The microstrip ring elements are more compact than the traditional reflectarray elements and can minimize blockage for the multilayer multifrequency applications. The highest efficiencies measured are 46% at 7.3 GHz and 38% at 31.75 GHz. The tested cross-polarization levels are -21 dB at 7.3 GHz and -29.2 dB at 31.75 GHz at the broadside direction. The tested results show that the designed ring element is suitable for both the single and dual layer applications with good bandwidth and circularly polarized performance.     

Ku 波段口径耦合宽带双极化微带天线

本文综合运用双层贴片和口径耦合馈电拓展了微带天线的带宽,设计了一个工作在Ku 波段的宽频带双极化 微带天线。利用在架高层介质上开腔体的方法实现对于寄生贴片的架高,既能有效降低天线成本,又可实现较低的等 效介电常数。基于这种双极化单元组成了一个2×2 的微带天线阵列,仿真结果表明两端口分别拥有20.5%和20.1%的 阻抗带宽,两端口隔离度大于31dB,水平极化和垂直极化的极化隔离大于41dB 和46dB。     

一种新型极化捷变有源微带天线阵

本文提出了一种新颖的极化捷变放大器型有源微带天线阵,只要在馈电端电控单一有源电路就能实现整个微带天线面阵极化的捷变和信号的放大.利用角馈方形微带贴片设计了一副具有高隔离度和低交叉极化的新颖16元双极化面阵,并分析了天线阵的共极化和交叉极化方向图.介绍了有源电路的设计.该电路利用一专用电控移相器,通过改变场效应管(FET)栅极的直流控制电压,电控两极化端口间的0°或90°相差,实现天线阵由线极化到圆极化的捷变.低噪声放大器(LNA)不仅使有源天线增益提高12-14dB,而且改善了天线的驻波比带宽和隔离度.文中给出了无源双极化阵和有源阵的实验结果,证实了理论的有效性.     

双频段双极化微带天线阵列设计*

设计了一种双频段双极化的阵列天线。该阵列天线采用多层微带天线形式,七层结构,通过口径耦 合和微带线边馈两种馈电方式实现双线极化,在辐射贴片上方增加寄生贴片以扩展带宽,实现双频段。天线工作在 12.25 ~12.75GHz 及14 ~ 14.5GHz,实测增益18dB 左右,隔离度大于40dB。该天线剖面低,重量轻,可作为子阵组 成更大规模的双频段双极化阵列。     

双频宽带大型微带反射阵天线设计

微带反射阵天线在性能上最主要的缺陷就是窄带,一般情况下其带宽小于5%,对电大口径短焦距馈电时更窄。本文设计并制作出一种由L波段和C波段两个反射面天线组成的6m×2m薄膜双频微带反射阵天线,两个频段的天线共用一层膜面。对该天线的电性能进行了测试,测试结果表明:该天线两个频段的相对带宽均大于10%(副瓣电平≤-18dB)。该天线具有折叠、可展开的结构特征,可以在卫星或航天器上广泛应用。     

Design and performance of a microstrip reflectarray antenna

Microstrip reflectarray antennas present an alternative to conventional directive antennas in that they are flat, inexpensive, easy to install and manufacture, conformal to the mounting surface, easy to package, and they possess high power and beam steering capabilities. For the first time, a comprehensive, experimentally verified design procedure for the microstrip reflectarray is presented. In this design procedure, the microstrip reflectarray has been shown to be an effective linear array capable of beam switching and dual polarization. The design procedure also allows the array to be fed from a feed-horn offset at any given angle to the plane of the array. The design procedure is well suited for CAD programs     

一种P波段宽带双极化微带天线阵列

介绍了一种P波段宽带双极化微带天线单元及2元阵列的设计。天线单元设计中采用口径耦合理论和多层贴片结构,增大了天线的带宽,两个极化端口采用共面馈电;馈电网络设计中采用反相馈电技术有效抑制了交叉极化,采用短路耦合线实现反相馈电,降低了对天线带宽的影响。仿真结果表明,该天线阵实际增益达到11.8dB,水平极化端口在0.68～0.86GHz频率范围内驻波比小于2,相对带宽为24%;垂直极化端口在0.63～0.86GHz频率范围内驻波比小于2,相对带宽为30.6%,两端口隔离度高于40dB。     

高隔离度双极化微带天线直线阵的设计

本文介绍一种新型的1×16双极化微带天线直线阵的设计.该天线采用双极化角馈方形贴片单元,阵列的垂直极化端口采用共面馈电,水平极化端口采用口径耦合,并在馈电网络中应用反相馈电技术.实验结果表明,天线二端口驻波比小于1.5的相对带宽分别达到15％和13.5％,两端口之间的隔离度在频带内高于33dB,最大达到43dB.本直线阵可用作星载综合口径雷达系统的天线子阵,便于与有源收发器件结合.     

High isolation dual-polarized patch antenna using integrated defected ground structure

This letter presents a high isolation dual-frequency orthogonally polarized rectangular patch antenna utilizing microstrip feed line integrated with a defected ground structure (DGS). The demonstrated approach results in a significant improvement in port isolation in comparison to a conventional dual-polarized antenna fed by simple microstrip lines. Measurements show an improvement of 20 dB in port isolation relative to the conventional antenna, operating at 2 and 2.5 GHz. Image impedance of a microstrip line with DGS is controlled by the DGS geometry without modifying the dimension of the line. A 150 /spl Omega/ high impedance line is effectively implemented using a microstrip line with 75 /spl Omega/ line width by incorporating the DGS.     

宽带宽角扫描双极化阵列天线设计

设计了一种宽带宽角扫描双极化vivaldi阵列天线。通过微带线向槽线耦合馈电,设计了工作于1～6 GHz的vivaldi双极化天线阵,并对加工的实物进行了测试。阵中单元驻波小于1.5,天线阵两维扫描角度达到±60°。试验结果表明,该天线在电子对抗、宽带通信等领域具有很大的应用价值。     

An integrated active microstrip reflectarray element with an internal amplifier

A new active microstrip reflectarray element (unit cell) with an internal microwave integrated circuit amplifier is introduced. The amplifier resides in a small slot within the footprint of the square patch antenna and is connected between the feed points for the patch's orthogonal polarizations. This element results in reduced array element spacing, reduced transmission line losses through elimination of long feed lines, and a simplified fabrication process compared to other active reflectarray unit cells. Patch geometries with several slot shapes are studied with simulations to arrive at an antenna configuration with good return loss and isolation characteristics. The stability and gain of the system are analyzed over frequency. Measured radiation pattern and gain data for a single element and a small array agree well with predictions and demonstrate the element's capabilities. Limitations of the active element, approaches to mitigate these limitations, and directions for future work are discussed.     

A Wide-Band 12-GHz 12-Way Planar Power Divider/Combiner (Short Paper)

A 12-way, low-loss, wide-band planar electrically symmetric hybrid power divider/combiner for the X-band is described. It is a two-stage fork, 12-way hybrid realized completely in microstrip. A circuit design is given to maximize the match and isolation at band center. Over a frequency band of 10-13 GHz, this divider/combiner has an insertion loss of less than 1 dB and an isolation between output ports of better than 17 dB.