Microstrip-fed quasi-Yagi antenna with broadband characteristics

A compact and uniplanar antenna with broadband characteristics is presented. The novel Yagi-like printed dipole array antenna is fed by a microstrip-to-coplanar strip transition, and uses the truncated microstrip ground plane as its reflecting element. An X-band prototype measures a bandwidth of 17%. With 6.5 dB gain, 18 dB front-to-back ratio, and lower than -15 dB cross-polarisation level at 10 GHz     

基于砷化镓衬底的集成天线特性分析

介绍一种可以应用在系统集成(SOC)和芯片间通信方面的结构紧凑的平面天线,制造于砷化镓半绝缘衬底上的Z字型印刷偶极子天线由一个微带—共面转换器馈电。同时也介绍了一套测试天线特性的测试系统,测试结果表明进行芯片内部和芯片之间的无线互联是可行的。     

Analysis of infinite arrays of substrate-supported metal stripantennas

An electric field integral equation method is applied to a metal strip antenna on an electrically thick dielectric substrate of finite size in a uniform infinite array environment. An efficient solution is found using the method of moments. Metal strip folded dipole antennas are analyzed both with and without a coplanar strip feed line, and the effects of the substrate and feed line are investigated. A technique for minimizing the effect of feed line scattering is presented, and arrays of these elements are shown to be capable of good scanning performance over a wide range of beam-steer angles. A phased array simulator experiment is described and the measured results show good agreement with those obtained by analysis. The class of antenna elements studied may be fabricated using monolithic microwave integrated circuit (MMIC) technology, and the analysis described illustrates the expected characteristics for millimeter-wavelength phased arrays of this type     

A 220 GHz Single-Chip Receiver MMIC With Integrated Antenna

This letter presents the design and characterization of a 220 GHz microstrip single-chip receiver monolithic microwave integrated circuit (MMIC) with an integrated antenna in a 0.1 mum GaAs metamorphic high electron mobility transistor technology. The receiver MMIC consists of a novel slot-square substrate lens feed antenna, a three-stage low noise amplifier, and a sub-harmonically pumped resistive mixer. The receiver MMIC is mounted on a 12 mm silicon substrate lens which focuses the radiation from the calibration loads to the on-chip antenna through an opening in the backside metallization of the MMIC. The double sideband noise figure of this quasioptical receiver is as low as 8.4 dB (1750 K) at 220 GHz including the losses in the antenna and in the lens. To the best of the authors' knowledge, this work demonstrates the highest integration level versus operating frequency for a MMIC ever published, regardless of technology.     

Passive broadband millimetre-wave uniplanar MMIC balun

A new uniplanar monolithic microwave integrated circuit (MMIC) balun using lumped circuits is presented. The proposed planar balun consists of a wideband Wilkinson power divider and a broadband 180° phase shifter using novel series and parallel LC reflective terminating circuits. To demonstrate the design methodology, a 24?44 GHz MMIC balun was realised as a 1.4 mm _{GaAs chip. The measured return losses for the unbalanced and balanced ports are better than 212, 210 and 27 dB, respectively. The measured amplitude and phase imbalance between the two output ports are less than 0.5 dB and 7°, respectively, and maximum insertion loss is 5 dB.}     

移动台适用的平面型紧凑极化分集天线

给出一种适用于移动台的平面型紧凑极化分集天线。该天线由两个十字交叉的微带分支提供极化分集。每一分支都有单独的微带一垂直探针馈电系统，并在分支上蚀刻有一个细槽以提高两个端口的隔离度。通过电容加载大大缩短了分支长度。利用时域有限差分法，在900MHz频段对该天线进行了分析和优化。天线模型的测量结果与仿真结果基本吻合，在约5％的带宽内两个端口的隔离度大于20dB、回波损耗均低于-10dB。该天线两端口的包络相关系数远小于0．1，能够满足分集的要求。     

Uniplanar one-dimensional photonic-bandgap structures andresonators

This paper presents uniplanar one-dimensional (1-D) periodical structures, so-called photonic-bandgap (PBG) structures, and defect high-Q resonators for coplanar waveguide, coplanar strip line, and slot line. Proposed uniplanar PBG structures consist of 1-D periodically etched slots along a transmission line or alternating characteristic impedance series with wide band-stop filter characteristics. A stop bandwidth obtained is 2.8 GHz with a stopband rejection of 36.5 dB. This PBG performance can be easily improved if the number of cells or the filling factor is modified in a parametric analysis. Using uniplanar 1-D PBG structures, we demonstrate new high-Q defect resonators with full-wave simulation and measured results. These structures based on defect cavity or Fabry-Perot resonators consist of a center resonant line with two sides of PBG reflectors. They achieve a loaded Q of 247.3 and unloaded Q of 299.1. The proposed circuits should have many applications in monolithic and hybrid microwave integrated circuits     

Active 60 GHz front-end with integrated dielectric antenna

The hybrid integration of a dielectric antenna together with an MMIC low-noise amplifier in a 60 GHz front-end is presented. It is demonstrated how a low-loss substrate integrated dielectric antenna can efficiently be interconnected at miniature scale with the coplanar waveguide input of the MMIC. The experimentally obtained return loss is better than 11 dB from 55 to 65 GHz. Transmission path loss measurements of a wireless link confirm the low-loss potential of this approach for millimetre-wave front-ends.     

毫米波雷达四元微带双天线阵的研制

本文介绍了一种应用于收发分离体制毫米波雷达前端的小型微带阵列双天线.双天线包含两个四元并馈微带天线阵,共置于直径为18.6毫米的圆形衬底上,分别作为雷达前端的接收和发射天线.前端电路采用自行研制的毫米波雷达MMIC套片,利用MCM技术集成在与天线共型的圆形衬底上,与天线以背对背方式连接,采用小孔耦合技术进行场耦合.经过对天线和整个前端的测试,收发天线提供了10.5dB的增益,两天线问的隔离度优于-34dB,雷达前端具备良好的收发性能.     

Coplanar millimeter-wave ICs for W-band applications using 0.15μm pseudomorphic MODFETs

A small signal S-parameter and noise model for the cascode MODFET has been validated up to 120 GHz, allowing predictable monolithic microwave integrated circuit (MMIC) design up to W-band. The potential of coplanar waveguide technology to build compact, high performance system modules is demonstrated by means of passive and active MMIC components. The realized passive structures comprise a Wilkinson combiner/divider and a capacitively loaded ultra miniature branch line coupler. For both building blocks, very good agreement between the measured and modeled data is achieved up to 120 GHz. Based on the accurate design database, two versions of compact integrated amplifiers utilizing cascode devices for application in the 90-120 GHz frequency range were designed and fabricated. The MMICs have 26.3 dB and 20 dB gain at 91 GHz and 110 GHz, respectively. A noise figure of 6.4 dB was measured at 110 GHz. The 90-100 GHz amplifier was integrated with an MMIC tunable oscillator resulting in a W-band source delivering more than 6 dBm output power from 94 to 98 GHz     

Dual-polarized dielectric resonator antennas

Two high input-isolation dual-polarized dielectric resonator (DR) antennas are presented in this communication. First, a slot-coupled feed technique with two narrow slots forming a "T" configuration is employed to design a dual-polarized DR antenna. Input isolation exceeding 35 dB has been obtained in the band for this design. Secondly, a hybrid feed mechanism with a coplanar waveguide (CPW) feed and a slot feed is used to achieve a dual-polarized DR antenna. A vertical strip is added at the center strip of the CPW feed to improve the coupling to the DR antenna. Also, input isolation exceeding 35 dB has been obtained in the band. Good cross-polarization levels less than -20 dB in the broadside direction are attained. The measured far-field radiation patterns are stable in the passband and the measured gains are around 5.5 dBi for the two feed ports of both cases.     

On the modeling of metal strip antennas contiguous with the edge ofelectrically thick finite size dielectric substrates

A solution to the problem of radiation by a narrow metal strip antenna contiguous with the edge of a dielectric substrate is presented where the substrate has parameters such that its electrical thickness is appreciable. Such an antenna may be useful at millimeter wavelengths as an integrated phased array element forming a part of a monolithic microwave integrated circuit (MMIC). A suitable geometry for this application is illustrated and an efficient computational procedure developed. Comparisons with experimental results for the input impedance and far-field radiation patterns show excellent agreement. The influence of the dielectric substrate on the performance of an antenna designed to operate at approximately 60 GHz is discussed. Two examples, the first involving the analysis of a coplanar strip transmission line fed antenna and the second involving impedance matching and control of cross-polarized radiation using a folded strip dipole, are given to illustrate practical applications of the analytical method to design problems     

一种新型宽带印制天线

本文给出了一种新型双偶极子型宽带印制天线,并设计出相应的类平行宽边耦合双线双面馈电结构。采用矩量法求解积分方程进行理论分析,由此设计出一种新型宽带印制天线,并进行实验测试。理论分析表明：在相同的基片上,双偶极子型印制天线比普通微带振子天线的带宽宽得多;同时实测结果表明：在0.8mm的介质基片上,工作于中心频率2GHz的该新型天线带宽可达23％（VSWR＜2.0）,增益达4.3dBi。该宽带天线为平面印制结构,易于与电路集成,亦可做为天线阵元,成本低,性能好。     

Wideband Circularly Polarized Dielectric Resonator Antenna

A circularly polarized quadruple strip feed cylindrical dielectric resonator antenna utilizing a pair of 90deg hybrid couplers is investigated experimentally. The antenna is shown to deliver an impedance bandwidth (S₁₁ < -10 dB) of 34.5%, from 1.75 to 2.48 GHz, and an axial-ratio bandwidth (AR < 3 dB) of 25.9%, from 1.65 to 2.14 GHz. The gain and radiation patterns are found to be stable within the passband.     

振荡型有源集成天线

研制中心频率为18 GHz的振荡型有源集成天线,包括微带天线设计、单片压控振荡器(MMIC VCO)的设计及微带天线与单片压控振荡器二者的集成。微带天线的芯片面积为4.5 mm×3.5 mm,增益为3.67 dB,中心频率为18.032 GHz,最小输入驻波系数为1.098;单片压控振荡器芯片面积1.1 mm×1.0 mm,调谐范围为15.978～18.247 GHz,输出功率大于6 dBm。振荡型有源集成天线的方向图测试结果与微带天线的特性符合,该振荡型有源集成天线能够正常工作。     

Planar millimeter-wave antennas using SiNx-membranes onGaAs

Planar aperture coupled microstrip antennas for 77 GHz are demonstrated for the first time. As far as possible standard GaAs monolithic microwave/millimeter-wave integrated circuit (MMIC) technology is used to realize the antennas. The antenna patches are suspended on a thin dielectric SiN_x membrane on GaAs substrate. Therefore a novel plasma-enhanced chemical vapor deposition (PECVD) process step for the fabrication of the membranes is developed and described. The single antenna patches are coupled to a microstrip line through an aperture in the ground metallization. The method of moments in spectral domain is applied to design the patches. The feed network of a 3×1 antenna array for homogeneous excitation is simulated and optimized with a microwave design system (MDS). From reflection measurements the operation frequency of this triple patch antenna is determined to be 77.6 GHz. The farfield antenna characteristics are measured in an anechoic chamber, showing good agreement between simulated and measured results and a co- to cross-polarization isolation better than 30 dB     

Uniplanar monolithic frequency doublers

GaAs monolithic frequency doublers in the 13-GHz band and 26-GHz band were designed and fabricated. These doublers use a uniplanar monolithic microwave IC (MMIC) structure. They are composed of coplanar waveguides, slotlines, and air bridges only on the upper side of the GaAs substrate. These uniplanar MMIC frequency doublers offer the advantages of smaller circuit size and simpler fabrication processes than microstrip-based MMICs. The fabricated doublers achieve a conversion gain of 2.9 dB at 12.4 GHz and a minimum conversion loss of 0.7 dB at 24.4 GHz. A 6.5-26.0-GHz frequency quadrupler is presented that uses a cascade connection of the doubler chips. It demonstrated stable operation without any adjustment and achieved a conversion loss of 10 dB     

利用EBG 结构减少手机辐射对人体的影响

基于时域有限差分法，研究了利用EBG结构减小手机辐射对人脑的影响。本文提出一种新型的平面型EBG结构，其结构为四周开槽型的方形贴片。将其加载到手机PIFA天线上，然后利用SEMCAD软件，在加载和不加载两种情况下，分别对人脑特定比吸收率(SAR)进行仿真分析和计算。分析结果表明：通过有效使用EBG结构加载技术，可以明显降低手机天线对人体方向的辐射，同时降低人体比吸收率SAR值。     

Broad-band uniplanar hybrid-ring and branch-line couplers

Novel uniplanar 180° and 190° hybrids suitable for MIC and MMIC applications are described. The uniplanar crossover hybrid-ring coupler using a coplanar waveguide (CPW) and slotline provides substantially improved amplitude and phase characteristics over a broad bandwidth compared to conventional microstrip hybrid-ring couplers. Experimental results show that the new coupler has a bandwidth of more than one octave from 2 GHz to 4 GHz with a ±0.4-dB power dividing balance and a ±1° phase balance. A uniplanar two-branch directional coupler using a coupled rectangular slotline ring has also been developed. CPW-to-slotline transitions using uniform and nonuniform CPWs or slotlines are also discussed. These transitions are uniplanar and simple to fabricate. No via-holes are needed for ground connections, and integration with solid-state devices is easy. A pair of broadband transitions using CPW shorts and slotline radial stubs is demonstrated with a 1-dB bandwidth of more than 5.2:1     

Broadband dual-polarized patch antennas fed by capacitively coupledfeed and slot-coupled feed

Designs of broadband dual-polarized patch antennas fed by promising feed structures of a capacitively coupled feed and a slot-coupled feed (antenna A), two capacitively coupled feeds of a 180° phase shift and a slot-coupled feed (antenna B), and two capacitively coupled feeds of a 180° phase shift and two slot-coupled feeds (antenna C) are proposed and experimentally studied. The first two feed designs are for the excitation of a single-element broadband patch antenna, while the last design is for a two-element broadband patch antenna. These proposed patch antennas have a thick air substrate, and the 10 dB return-loss impedance bandwidths obtained for the two polarizations are all greater than 13%. High isolation (<-30 dB for antenna A, <-32 dB for antenna B, <-35 dB for antenna C) between the two feeding ports for the entire impedance bandwidth of the proposed antennas can be obtained. Also, improved cross-polarization levels (>20 dB) in both E and H plane patterns for the two polarizations of antennas B and C are achieved