High-gain and high-efficiency single-layer slotted waveguide arrayfor use in 22 GHz band

A slotted waveguide planar array using a single-layer feed circuit is proposed for high-frequency and high-gain antennas. The high efficiency of 75.6% and the gain of 35.9 dBi are obtained in the 22 GHz band, which confirms the potential of this type of antenna. The antenna consists of only two components, a slotted plate and a groove feed structure, and can be mass produced     

Center feed single layer slotted waveguide array

A center feed configuration is newly introduced to enhance the bandwidth as well as to suppress the frequency dependent beam squinting in single layer slotted waveguide arrays. A multiple-way power divider consisting of cross-junctions is installed at the center of the aperture in an alternating-phase fed waveguide slot array to reduce the long line effect in the radiating waveguide. Each radiating slot is equipped with an inductive wall for reflection canceling, which dispenses with the beam tilting technique for suppressing cumulative reflection and assures the boresight beam. All these are equipped in single layer and are potential for low cost mass-production as is usual the case with alternating phase-fed arrays. The test antenna is fabricated at 26GHz band for FWA system. A 30.5 dBi gain with 46% efficiency with the main beam staying in the boresight is obtained. The sidelobes of -9.5 dB associated with the aperture blockage for the center feed is suppressed to below -14.7 dB at the design frequency, by applying a genetic algorithm for controlling the slot excitation.     

Interpretation of scattering phenomenology in slotted waveguidestructures via time-frequency processing

The scattering phenomenology in slotted waveguide structures is investigated using time-frequency processing of numerically simulated data. Two geometries are studied, a finite waveguide with one slot on each end and a linear slotted waveguide array comprised of 16 equally spaced slots. The numerical simulation is accomplished via a three-dimensional moment-method procedure in conjunction with a connection scheme which makes possible the simulation of a long waveguide structure spanning over 32 wavelengths at 10 GHz. The resulting numerical data are then processed using the short-time Fourier transform to identify the dominant scattering mechanisms. In the joint time-frequency plane, the unique scattering physics associated with slotted waveguide structures are more clearly revealed. In particular, the Floquet harmonics due to the exterior slot structure, the dispersion due to the interior waveguide modes, and the “interior Floquet” phenomenon can be readily identified and fully interpreted     

A two-beam slotted leaky waveguide array for mobile reception ofdual-polarization DBS

A two-beam slotted leaky waveguide array for mobile reception of dual-polarization direct broadcast from satellite (DBS) is realized in a single-layer structure. Two feed waveguides attached at both ends of cross-slotted radiating waveguides excite the leaky waves propagating in opposite directions. Each of them radiates either of two circularly polarized waves in symmetrical beam directions. Balanced design of two beams for each polarization imposes symmetry in the array design of slots. The slot coupling distribution is optimized for the maximum gain under this symmetry condition. A model antenna in about a 300-mm square is fabricated for experiments in the 12-GHz band. Antenna efficiency of 71% and 64% is obtained for each beam in different polarizations     

Imperfect sector antenna diversity in slotted ALOHA mobile network

In a wireless network with path loss and fading channels, receiver capture is known to substantially enhance the performance of the slotted ALOHA random access protocol. The efficiency of narrowband slotted ALOHA radio networks can be enhanced further by using sector antennas, each receiving signals from a particular segment of the network area. This paper investigates the effect of realistic, i.e., partially overlapping antenna patterns and the resulting correlation of received power levels at different receiver branches. A method is derived for computing the joint throughput from two base station receivers with overlapping antennas patterns. The a posteriori information provided by the event of one message capturing one antenna is used to find conditional probabilities of capturing the other antennas as well. The paper shows that any overlap in the antenna patterns decreases the throughput, but transmissions from the overlapping area may face a larger probability of capture than signals from directions in which one antenna has maximum gain     

一种旁瓣匿影天线系统设计

旁瓣匿影是相控阵雷达采用的一种典型抗干扰技术。天线系统是旁瓣匿影的核心硬件设备,其设计直接关系到匿影波束能否有效压制干扰信号。针对目前旁瓣匿影容易出现的波束覆盖穿刺等问题,文中设计了一种旁瓣匿影天线系统,它包括全向匿影天线、低噪放耦合模块。通过匿影天线与低噪放集成设计提高匿影链路的干噪比。全向匿影天线采用方位全向双极化天线设计,水平极化匿影天线采用扁波导缝隙全向天线,垂直极化匿影天线采用扁平双锥全向天线。仿真结果表明,两种天线可实现方位向水平极化与垂直极化的全向覆盖。经实测验证,匿影波束能完整覆盖主天线副瓣区,可有效提升雷达系统的抗干扰能力。     

Grating lobes caused by parallel-plate polariser

An unexpected high-level sidelobe was encountered when a parallel-plate polariser was fitted to a slotted waveguide array. The phenomenon is explained using grating lobe theory and linear near-field measurements. A technique to suppress the grating lobe is proposed.     

双频段双极化共孔径阵列馈源反射面天线设计

介绍了一种新型Ku/Ka双频段双极化共孔径阵列馈源偏馈抛物柱反射面天线的设计。在双频段双极化共孔径阵列馈源设计中,Ka波段采用裂缝波导阵,并且位于共孔径馈源阵列的下层,双极化Ku波段采用微带贴片天线、位于共孔径阵列馈源的上层。文中给出了该双频段双极化共孔径阵列馈源的设计及测试结果,并将该测试结果代入偏馈抛物柱反射面天线中在FEKO软件平台上进行了半实物仿真,仿真结果表明,该双频段双极化共孔径阵列馈源偏馈抛物柱反射天线实现了如下设计目标:Ku波段双极化水平面扫描范围为±17°,两个主面副瓣电平优于-30dB,Ka波段水平面扫描范围为±10°,两个主面的副瓣电平优于-30dB,双频段双极化两个主面的波瓣宽度和波束指向完全匹配。     

Grating Lobe Suppression of Narrow-Wall Slotted Hollow Waveguide Millimeter-Wave Planar Antenna for Arbitrarily Linear Polarization

A high-gain and high-efficiency slotted waveguide planar antenna is developed in the millimeter-wave band. Forty-five degree inclined polarization is required for automotive radar systems. In the design of slotted waveguide array for arbitrarily linear polarization, slot spacing is one guide wavelength which is larger than a wavelength in free space. Consequently, grating lobes appear in the radiation pattern. So, we developed a slotted waveguide planar antenna composed of post-loaded narrow-wall slots and a single-layer alternating-phase feeding circuit. A planar antenna with suppressed grating lobes has been fabricated and its RF performance has been measured. The measured gain is 33.2 dBi and antenna efficiency is 56% at 76 GHz. Grating lobe level is -28.6 dB lower than main lobe level. Since the proposed structure remains simple, the antenna is expected to be manufactured by metal injection molding for low cost     

The design of linearly polarized slotted waveguide feeds for spherical reflectors

A procedure for the design of linearly polarized slotted waveguide line feeds for spherical reflector antennas is described. The necessary equations for determining the complex propagation constantalpha + jbetain a line source are given in terms of reflector parameters. Guide and slot dimensions that will yield the desiredalphaandbetaare then found by making use of experimental data, presented herein. These data consist of measured values ofalphaandbetaas functions of slot length for a number of slotted waveguide test sections of various widths. The technique is applicable over a wide range of frequencies and reflector sizes. An example is given in which a feed is designed at 1420 MHz to illuminate 700 ft of aperture in the Arecibo spherical reflector.     

X 波段加膜片式单脊波导裂缝天线的研究

等效导纳值是波导宽边纵缝天线的关键设计参数。为克服传统波导裂缝天线副瓣偏高、设计效率低下等问题,本文提出了一种单脊波导裂缝天线的改进设计方法,在传统波导裂缝阵列天线设计的基础上,利用等效导纳值对天线等效电路的影响,在裂缝单元下增加金属膜片,通过改变金属膜片的高度,优化裂缝等效导纳值,使得每个裂缝口径场分布更加接近于理论设计值,并在设计过程中使用牛顿迭代法提取导纳进一步缩短设计时间。通过设计实例表明:应用此方法设计单脊波导裂缝天线能够有效抑制副瓣电平,天线方位面副瓣电平可达到-30 dB 以下;在满足主要指标要求的前提下,设计效率显著提升。     

Arrays of horizontally polarized loop-fed slotted cylinder antennas

Measured center element gain patterns, voltage standing-wave ratio (VSWR), and mutual coupling for passively terminated arrays of horizontally polarized loop-fed slotted cylinder antennas over a ground plane are given. A seven-element hexagonal array is investigated in detail. The element gain pattern is shown to have a null at broadside with omnidirectional coverage along a constant cone angle from broadside. Maximum gain occurs close to50degfrom broadside which provides for wide-angle phased array scanning capability. The antennas are also configured in a linear array geometry, to investigate mutual coupling effects on the element gain pattern as the number of elements is varied. The element gain pattern is shown to converge for a relatively few number of elements and there is no indication of undesired blind spots.     

Time-domain properties of a waveguide slotted antenna array

Extremely high-frequency radiation of a waveguide slotted antenna array (WSAA) transmitting a pulse signal is studied. An algorithm and a technique of calculation of the transient impulse response of the WSAA are developed. It is shown that a radio pulse with a center frequency of 35 GHz and a bandwidth of 2 GHz is transmitted without distortions through the array optimized for 35 GHz.     

Compact triple-band slotted monopole antenna with asymmetrical CPW grounds

By embedding slots into a rectangular patch a triple-band slotted monopole antenna fed by a coplanar waveguide (CPW) with two asymmetrical ground planes can be obtained. The designed antenna, which, including the ground plane, is only 9/spl times/20 mm/sup 2/, can excite resonant modes at 2.43, 5.23 and 7.14 GHz bands with measured impedance bandwidths of 14.4, 8.2 and 16.7%, and average antenna gains of /spl ges/2.4, 4.7 and 6.7 dBi, respectively. The antenna is very compact and suitable for 2.4/5.2 GHz WLAN operations.     

低耗低剖面单层波导阵列天线研究

新型单层波导阵列天线具有低耗、低剖面、结构紧凑、实用性强等诸多优点, 在毫米波甚至太赫兹无线通信领域具有巨大应用潜力, 是当前的研究热点。 文章首先介绍了用于构建波导阵列天线的几类波导馈电网络的特点, 指出E 面波导馈电网络在毫米波应用领域的优势,接着针对E 面波导在单层并馈波导阵列天线和Butler矩阵多波束阵列天线方面的研究展开叙述,最后给出了可应用在单层波导阵列天线中的开口波导辐射单元在实现多频和圆极化等不同功能上的最新研究进展。 文章对于低耗低剖面单层波导阵列天线的发展及其应用具有参考价值。     

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique, are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analyzed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies.      

新型X波段波导缝隙阵列天线的设计

为了克服传统波导缝隙阵列天线重量大、副瓣偏高等问题,提出一种小型化、低副瓣X波段波导缝隙阵列天线的设计方法。首先采用高斯分布实现其幅度加权,快速完成低副瓣波导缝隙阵列天线的设计;然后结合HFSS 软件对传统压缩波导的窄边尺寸进行优化,减小窄边尺寸;同时采用3D 打印技术制造ABS 塑料波导缝隙框架和金属电镀工艺实现天线的加工,通过仿真分析和实物加工测试验证了所设计天线的有效性。所设计的天线方位面副瓣电平可达到-25 dB 以下,重量从25 kg 减小到2.5 kg,减重比达到了90%。最后,详细分析了不同金属电镀层厚度对天线性能的影响。     

新型快速波导缝隙天线设计方法

对馈电网络和天线的散射矩阵进行级联,推导了互耦条件下阵列天线输入端口散射参数和天线实际激励分布的计算方法。基于该方法,提出了一种新型快速波导缝隙天线设计方法,并设计了一副12 元宽边纵缝一维波导缝隙天线。测试结果表明,在9. 82 ~10. 21 GHz 内反射系数和副瓣电平分别优于-15 dB 和-28 dB。测试结果与计算、仿真结果吻合良好,验证了该方法的准确性和有效性。     

Synthesis of Thinned Multiple Concentric Circular Ring Array Antennas using Particle Swarm Optimization

In this paper, we propose an optimization method based on Particle Swarm Optimization (PSO) algorithm for thinning a large multiple concentric circular ring array of uniformly excited isotropic antennas and generate a pencil beam in the vertical plane with minimum relative side lobe level (SLL). The half-power beam width of the pattern is attempted to make equal to that of a fully populated array of same size and shape. The synthesis is performed with a standard particle swarm optimization technique as well as with an improved version of standard PSO. Simulation results of the proposed thinned array are compared with a fully populated array to illustrate the effectiveness of our proposed method.     

Periodically slotted dielectrically filled parallel-plate waveguideas a leaky-wave antenna: E-polarization case

The analysis of a periodically slotted dielectrically filled parallel-plate waveguide as a leaky-wave antenna for infinite and finite periodic structures for the E-polarization case is discussed. For the analysis of the infinite periodic structure, an integral equation in which Floquet's modes and the strip electric current satisfying the edge condition are used and Bloch wave analysis using the single-slot equivalent circuit parameters are employed. An integro-differential equation with moment-method and transmission-line analysis with equivalent circuit representation are used to analyze the finite N-periodic structure. Results of interest such as complex propagation constant and the radiation pattern for the finite slot number case are observed to be in good agreement with those of the infinite geometry case for the appropriately chosen values of slot numbers, slot width, period, and waveguide height