W 波段圆极化微带阵列天线设计

本文分析和对比了W 波段圆极化微带阵列天线不同的馈电形式,完成了圆极化阵列天线的设计。由理论分析 和仿真结果可知,单元间等幅同相馈电有利于W 波段圆极化微带阵列天线的实现,其2x2 阵列天线仿真结果驻波小于2 的相对带宽为3.5%, 轴比小于3dB 带宽为2%,中心频点94GHz 时天线增益为12.2dB。该天线在军事领域具有广泛的应 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.     

圆环相控阵天线瞬时带宽的分析与计算

相控阵天线需要足够的瞬时带宽以满足无线通信系统的性能要求.分析了限制圆环相控阵天线瞬时带宽的影响因素,主要包括频率变化引起的天线波束指向偏差和天线孔径渡越时间对瞬时带宽的限制.比较了圆环相控阵天线与线阵相控阵天线瞬时带宽的异同,并给出了圆环相控阵天线瞬时带宽的计算方法,为圆环相控阵天线的设计提供了理论指导.     

Circularly polarised patch antenna array using proximity-coupledL-strip line feed

A microstrip antenna array for circular polarisation (CP) using a proximity L-strip line feed is proposed and experimentally investigated. By placing a cross-slot with unequal slot lengths on the circular patch, circular polarisation can be excited. Also, a sequential rotation technique is adopted for the design of this CP antenna array to widen the bandwidth. The impedance and axial ratio bandwidth values are 78 and 16.15%, respectively. The boresight axial ratio is 0.4 dB at 1.91 GHz     

微带方形缝隙天线的阵列设计

根据理论分析的结果,设计了中心频率为35 GHz的微带方形缝隙直线天线阵列与圆环天线阵列。通过计算机仿真技术(Computer Simulation Technology,CST)微波工作室仿真可知,直线阵列的方向性系数达到17.32 dBi,当电压驻波比(Voltage Standing Wave Ratio,VSWR)小于2时带宽为4.371 GHz;圆环阵列的方向性达到10.1 dBi,带宽为5.07 GHz(VSWR<2)。因此其符合相控阵雷达的要求。     

Ka频段宽带圆极化微带天线

面向Ka频段高通量卫星对天线的需求,设计了一种Ka频段宽带圆极化微带天线.天线单元主要由圆形辐射贴片和缝隙耦合馈电结构组成,通过两个类T形缝隙结合实现宽带圆极化.天线仅有三层金属层,结构简单.仿真结果显示,天线单元的相对阻抗带宽为31.5%(25.1～34.5 GHz),相对3 dB轴比带宽为20.3%(26.5～32.5 GHz).由于单元尺寸较小,不便于对其性能进行验证,因此利用该天线单元组成2×2天线阵列,并进行加工测试.仿真与试验结果表明,天线阵列阻抗带宽以及3 dB轴比带宽可以覆盖25.6～33.1 GHz频率范围,实测结果与仿真结果一致性良好.     

Single-feed circularly polarized microstrip ring antenna and arrays

An analysis is presented for a microstrip-feed proximity-coupled ring antenna and a four-element array. Interactions between the embedded microstrip feed and the radiating element(s) are rigorously included. Results demonstrate that circular polarization of both senses can be achieved with a ring antenna with proper design of two inner stubs located at angles of ±45° with respect to the feedline. Theory and experiment demonstrate an axial ratio 3-dB bandwidth of 1% and the voltage standing wave ratio (VSWR) <2 bandwidth of 6.1%. The axial ratio bandwidth is typical for a microstrip antenna with perturbations, while the VSWR bandwidth is larger than for the circular or rectangular patch with perturbations. A mutual coupling study between two elements shows that the axial ratio is less than 2 dB for interelement spacing greater than 0.55λ_eff, while the VSWR <2 for all spacings considered. A comparison between theory and experiment is provided for a 2×2 element array. The benefits of sequentially rotating the antenna elements in an array environment are presented. The axial ratio and VSWR bandwidths are both increased to 6.1% and 18% for a four-element array. A single-element antenna with two orthogonal feeds to provide both senses of polarization is demonstrated. The ring antenna is small (D/λ₀=0.325), the substrate thickness is thin (H/λ₀~0.035), and the microstrip feed produces a completely planar antenna system, which is compatible with microwave and millimeter integrated circuits (MICs), and monolithic microwave integrated circuits (MMICs)     

一种新型Ka频段圆极化微带天线设计

提出了一种Ka频段圆极化微带天线的新设计,采用缝隙耦合馈电方式,通过在接地板开L型缝隙实现天线的圆极化工作。对天线阵列进行了仿真优化和加工实测,仿真和测试结果表明了设计的可行性。天线仿真和实测的相对阻抗带宽分别为3.9%和4.2%,仿真和实测的轴比相对带宽分别为2%和3.5%。天线具有良好的圆极化特性,可应用在卫星通信中。     

Sequentially rotated large bandwidth circularly polarised printedantennas

Four printed travelling-wave elements having 66% bandwidth are sequentially rotated in a 2×2 array. Computed and measured circular polarisation characteristics of the array with and without sequential rotation, are critically examined and the advantages and disadvantages of the sequential design technique are identified. Practical implementation and the inference for other types of large bandwidth elements and arrays are noted     

Broadband printed ring-slot array with circular polarisation

A novel design of a printed ring-slot antenna with circular polarisation (CP) is first proposed. The CP radiation of the slot antenna is achieved by a series microstrip-line feed configuration. Using the single CP slot antenna as an array element, the 1times2 and 2times2 slot arrays are constructed and measured. To obtain wider CP bandwidth, phase sequential rotation technique is applied to the feed network of these printed slot arrays. The experimental results show that the 2times2 slot array antenna is capable of 15% bandwidth for an axial ratio of less than 3 dB     

64 单元X 波段高增益圆极化微带阵列天线设计

采用双层矩形贴片加切角的结构设计圆极化单元,并将其组成应用于X 波段64 单元高增益圆极化微带阵列天线。天线基板采用Taconic-TRF,介电常数4. 5,厚度0. 81mm,损耗角正切0. 0035。利用Ansoft HF-SS 软件对单元及阵列模型进行仿真优化。通过实际测试,64 单元阵列天线轴比AR<6dB 的带宽500MHz,增益达到21. 2dB,S11 <-10dB 的相对阻抗带宽达到6. 9%,天线具有良好的圆极化和阻抗匹配特性。圆极化天线具有较强的抗干扰能力,可很好地应用于电子侦察、电子对抗等领域。设计的圆极化微带阵列天线为组成更大阵列的天线以及构建相控阵天线提供了单元基础。     

新型强耦合宽带双圆极化阵列天线

空间飞行器由于受到动力和负载的限制, 需要尽可能使搭载的天线轻质小型化.文中提出了一种新型强耦合双圆极化轻质天线.天线单元采用H型缝隙耦合和增加寄生贴片方法, 提高了天线带宽.同时, 通过在辐射贴片、寄生贴片上开圆形槽, 以及金属反射板栅格化的处理, 明显地减轻了天线的质量.采用这种新型天线单元, 设计了8单元的宽带双圆极化阵列天线.仿真结果表明:该阵列天线的中心频率为433 MHz, 左旋和右旋圆极化的相对轴比(Axial Ratio, AR)带宽(AR < 3 dB)分别达到了24.4%和23.2%, 有效实现了小型轻质化宽频带双圆极化阵列天线.     

宽带高增益圆极化微带天线与阵列

设计了一副宽带高增益圆极化微带天线,并进行组阵分析。天线中心频率2.6 GHz,通过增加寄生贴片和空气层来提高天线单元的增益和带宽。上下两层介质板上边长不同的切角方形贴片分别激励一个低频与高频的圆极化模,有效地拓宽了轴比带宽。仿真结果表明,反射系数|S11|<-10 dB带宽21.8%,3 dB轴比带宽12.0%,中心频率点增益9.0 dBi。对天线单元进行加工测试,与仿真结果较为吻合。设计了2×4元阵列,并进行了仿真,增益提升至17.5 dBi,3 dB轴比带宽10.4%。     

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.     

Low-Cost Broadband Circularly Polarized Printed Antennas and Array

This paper presents the design, simulation, and measurements of two low-cost broadband circularly polarized (CP) printed antennas: an element and an array at 2 GHz. To realize the broadband circularly polarized antenna element, a circular microstrip patch is electromagnetically coupled by crossed slots cut in the ground plane, which is fed by an L-shaped microstrip feed. Two orthogonal modes in the patch are excited by using the crossed slots, and a single L-shaped feed provides a 90deg phase shift between two orthogonal slots. The antenna element achieves a 9.6% bandwidth for an axial ratio (AR) below 3 dB and a voltage standing wave ratio (VSWR) below 1.5. To further improve the performance, a sequentially rotated feed network is designed for a 2 times 2 array. The axial ratio value of the array is below 3 dB within a 27.2% bandwidth, from 1.75 GHz to 2.3 GHz. The return loss is above 10 dB within a 41% bandwidth, from 1.62 GHz to 2.45 GHz. Details of the proposed antenna element and the array design are described, and both the simulation and the experimental results are presented and discussed.     

Large-bandwidth flat cylindrical array with circular polarisation and omnidirectional radiation

Experimental properties of a flat cylindrical array with circular polarisation and omnidirectional radiation are presented. The thickness of the array wrapped on a perfect conducting cylinder is 0.04?0. A bandwidth of 10% has been obtained. It is now possible to decrease the thickness by a factor 2 (i.e. to 0.02?0), when using a short-circuited elementary source instead of a flat folded dipole, and yet retain the same band-width.     

Broadband high-efficiency circularly polarized active antenna and array for RF front-end application

This paper presents a broadband high-efficiency circularly polarized (CP) active integrated antenna, and a broadband CP active array at 2 GHz. To realize the broadband CP antenna, a circular patch is aperture coupled by crossed slots in the ground plane, which are fed by an L-shaped microstrip feed line below the ground. The antenna is designed to serve the functions of both a radiator and a harmonics-terminated load for class-E high-efficiency power-amplifier (PA) integration. The broadband CP active antenna is realized by directly integrating the broadband CP antenna with the class-E PA. It achieves a 9% bandwidth (1.84-2.01 GHz) for axial ratio (AR) below 3 dB, and a 12% bandwidth for power-added efficiency (PAE) over 60%. To form the broadband CP active array, four active antenna elements are sequentially rotated, and each element is directly integrated with broadband class-E PA. A low-cost printed-circuit-board technology is employed in fabrication and a pseudomorphic high electron-mobility transistor is used. A peak drain efficiency of 71.5% for the class-E amplifier is measured at 1.95 GHz. The active array achieves a peak-effective radiated power of 39.7 dBm, and PAE is over 50% within a 22.6% bandwidth (1.72-2.16 GHz). The AR is below 3 dB over a 27% bandwidth (1.72-2.26 GHz).     

A Coaxial Wavewide Commutator Feed for a Scanning Circular Phased Array Antenna

A coaxial waveguide amplitude commutation feed system has been developed for application to the scanning circular array antenna problem. A dominant TEM mode and a pair of orthogonal TE/sub 11/ modes suitably excited at the input of a coaxial waveguide feed are employed to generate a simply commutatable low-sidelobe discrete amplitude distribution at the peripheral output ports of the coaxial circular array feed. The major advantages of the coaxial commutator feed compared to other circular array feed types are the broad bandwidth and small insertion loss simultaneously achieved with a simple feed geometry. The design and measured performance capability of a 30-percent RF bandwidth low-sidelobe coaxial commutator feed are described in detail.     

Novel Broadband Circularly Polarized Cavity-Backed Aperture Antenna With Traveling Wave Excitation

A novel broadband circularly polarized aperture antenna is presented that uses traveling-wave excitation as the design concept. The antenna configuration consists of a circular radiating aperture, a backed cavity, and an equiangular tapered strip outer-fed by a microstrip transmission line. Operating with a traveling wave excitation, the proposed antenna contains inherent broadband characteristics in terms of the impedance, axial ratio, and gain performances. The presented antenna is comprehensively investigated, including the working principles, design consideration, and parametric studies. In addition, the research interests are extended to a 2$,times,$ 2 antenna array. Promising results from the experimental 2$,times,$2 array are achieved, including the 10-dB return loss bandwidth of 70%, the 3-dB axial ratio bandwidth of 50%, and the half-power (3-dB) gain bandwidth of 40% with a maximum gain about 11 dBi. The measured and simulated results are well complied with each other.      

Circular array and nonsinusoidal waves

A theory of circular array antennas based on nonsinusoidal (rectangular) pulses, is developed. Different antenna patterns such as peak amplitude, peak power, energy, and slope pattern are derived and plotted. The antenna patterns yield the resolution angle for the circular array as a function of array radius and frequency bandwidth. The effect of additive Gaussian noise on the angular resolution capability of the circular array is analyzed. The analysis is based on calculating slope patterns by using linear regression algorithm for different signal-to-noise power ratios