Transverse slot antenna array in the broad wall of a rectangular waveguide partially filled with a dielectric slab

A compact and wide-band transverse slot antenna array in the broad wall of a rectangular waveguide partially filled with an H-plane -dielectric slab is presented in this paper. By partially filling an H-plane dielectric slab in the waveguide, the inter-element spacing between slots is reduced to be about 0.8 free-space wavelengths to avoid grating lobes. In addition, the partially filled material provides extra flexibility to adjust the slot impedance as desired within a relatively wide frequency range. A new feeding network is designed for this antenna array, which can prevent the shift in the pointing angle of the array's main radiation beam with the change of frequency. Experimental data for a 2/spl times/4 antenna array operating at X-band show that stable radiation pattern over a wide frequency range can be obtained. The measured gain is 16.9 dB at 10 GHz and the fluctuation is less than 2 dB over a frequency band of 1.5 GHz. The slot array's 10-dB return loss bandwidth is 13% and the cross-polarization level is better than -25 dB.     

Spatial power amplifier using a passive and active TEM waveguide concept

A new spatial power amplifier is presented in which power is spatially combined within a TEM waveguide using a low-loss transition array of E-plane integrated finlines to microstrip lines. The TEM-mode waveguide is implemented using a periodically patterned surface called a uniplanar compact electromagnetic bandgap (UC-EBG) structure. Our designed Ku-band back-to-back transition array demonstrates a maximum return loss of 17.5 dB and a maximum insertion loss of 0.65 dB. The TEM waveguide is found to have a 1-GHz bandwidth centered at 14.5 GHz. Tuning of the center frequency may be accomplished via an active UC-EBG structure that incorporates varactor diodes. The use of the UC-EBG surface allows more power cards to be inserted within the TEM waveguide since the amplifier cells saturate uniformly. The spatial power combiner is used to combine the output powers of 12 20-mW monolithic-microwave integrated-circuit amplifier chips. The designed power module yields an output power of 23.15 dBm and a combining efficiency of 86%. A comparison between the passive and active UC-EGB surfaces is experimentally demonstrated.     

新型双波段共面微带/波导单脉冲天线设计

提出了一种新型共面双波段单脉冲天线设计方法, 分别给出了两个频段的驻波曲线和辐射方向图的测试结果.该天线在有限的空间内采用小型化边缘馈电的微带天线阵列与波导缝隙天线阵列复合, 实现了两个频段的单脉冲天线共口径排布, 天线厚度29 mm, 重量小于1 kg.测试结果表明该新型双波段单脉冲天线能够在X、K两个特定频段下分别得到-19 dB和-22 dB的副瓣性能及38%和45%的辐射效率, 实现了与单模相当的单脉冲方向图性能, 满足了未来复合制导系统对高性能天线的需求.     

Coplanar waveguide fed quasi-Yagi antenna

A novel coplanar waveguide fed quasi-Yagi antenna is presented. A wide bandwidth is achieved by using a broadband coplanar waveguide to a slotline balun. An X-band prototype has been realised which demonstrates a broad bandwidth (30%), -19 dB front-to-back ratio, and cross-polarisation better than -17 dB at 10 GHz.     

脊波导缝隙圆极化天线的设计*

设计了一种新型脊波导缝隙圆极化天线。在脊波导宽边开并联纵缝,从波导耦合电磁波至其上方的四脊波导圆极化器,实现圆极化辐射。采用脊波导不仅减小了单元尺寸,更改善了天线的带宽性能。重点研究了四脊波导圆极化器对相互垂直的两辐射场分量的影响,优化单元的轴比特性。在提取单元谐振电导的基础上,设计了工作在10GHz 的1×10 圆极化波导缝隙阵列。对天线实物测试得到中心频率处的增益为16.8dB,第一副瓣电平为 25dB,阻抗带宽约为8.5%,相对轴比带宽(AR臆3dB)约为3.2%。     

基于T型谐振器的抗干扰矩形波导缝隙阵列天线设计

介绍了一种抗干扰矩形波导缝隙阵列天线的设计方法,仿真、设计并加工了一款基于T型谐振器的四缝隙矩形波导缝隙阵列天线. 通过在矩形波导下壁引入周期性的T型谐振器,有效提升了天线的抗干扰能力. 测试结果表明,该天线的?10 dB阻抗带宽为10.3%（5.5～6.1 GHz）,增益为11.5～12.8 dBi,天线效率为72.1%～87.3%。与传统矩形波导缝隙阵列天线相比较,本文设计天线在抑制频段 7.9～9.6 GHz的抗干扰能力提升了32.2～69.3 dB,适用于多频段、多任务的无线通信、雷达系统等.     

Optimum design of waveguide E-plane stub-loaded phaseshifters

Broadband low-insertion-loss E-plane stub-loaded rectangular waveguide phase shifters are designed with the method of field expansion into normalized eigenmodes, which includes higher-order mode interaction between the step discontinuities. Computer-optimized three-stub prototypes of 90° differential phase shift with reference to an empty waveguide of appropriate length, designed for R140-band (12.4-18 GHz) and R320-band (26.5-40 GHz) waveguides, achieve typically ±0.5° phase shift deviation within about 20% bandwidth. For two-stub designs, the corresponding values are about +2.5°/-1° and 17%. Both designs achieve minimum return loss of 30 dB. The theory is verified by measurements of a compact R120-band (10-15 GHz) waveguide phase shifter design example milled from a solid block, showing measured insertion loss of about 0.1 dB and about +2.5°/-0.5° phase error between 10.7 and 12.7 GHz     

Flat spectral response arrayed-waveguide grating multiplexer withparabolic waveguide horns

An eight-channel flat spectral response arrayed-waveguide grating multiplexer with parabolic waveguide horns has been fabricated on a planar lightwave circuit (PLC). A double-peaked intensity distribution is formed at the slab interface by the parabolic waveguide horn. A 1 dB bandwidth of 98 GHz, 3 dB bandwidth of 124 GHz and 20 dB bandwidth of 196 GHz are obtained for 200 GHz channel spacing. The crosstalk to neighbouring channels is less than -27 dB and the on-chip insertion losses range from 6.1 to 6.4 dB, respectively     

Laminated waveguide as radiating element for array applications

This paper reports on the study of a new antenna as well as a five-element array prototype developed for communications in K-band and suitable for low temperature co-fired ceramic technology. The radiating element is an open waveguide realized in laminated technology. A special coaxial-to-waveguide transition has also been designed as feed port for measuring the prototypes. The element exhibits a 1 GHz bandwidth centered at 20.7 GHz and a 2.7 dBi gain. In an array configuration, mutual coupling between the elements is lower than -18 dB across the bandwidth. The simulated boresight radiation pattern of a five-element array is stable over the bandwidth and the gain reaches 9.2 dBi at 20.7 GHz. The measurements of the radiation pattern for a 20-degree scan angle, as well as the simulation, demonstrate the scanning capability of this array.     

Slanted-rib waveguide InGaAsP-InP polarization converters

We summarize experimental and theoretical results for a compact (330 /spl mu/m), low-loss on-chip InGaAsP-InP polarization converter. The converter, which contains a single asymmetric rib waveguide segment, exhibits a measured conversion efficiency of -16 dB and a response of /spl plusmn/3 dB with a maximum excess loss of 0.02 dB over the entire wavelength region from 1530 to 1570 nm.     

多孔耦合型太赫兹波导定向耦合器的设计

设计了一种结构紧凑、工作频带较宽、耦合平稳、高方向性的十字形多孔耦合的太赫兹波导定向耦合器。基于多孔耦合原理,利用HFSS软件对太赫兹波导定向耦合器进行了模型仿真和结构优化。仿真结果表明:在325~475 GHz带宽范围内,该多孔耦合太赫兹波导定向耦合器耦合度达到7.50.8 dB,隔离度达到30 dB,即方向性优于20 dB,各端口回波损耗小于-20 dB。通过对该波导定向耦合器进行高温高压模拟仿真,确定了使用负性光刻胶SU-8作为结构材料的可行性,提出应用MEMS工艺在硅衬底上进行加工,将牺牲层工艺应用到波导腔结构的制作中。利用光刻在直通波导和耦合波导公共宽壁上形成的十字形等间距排列耦合孔结构,可以实现较宽的带宽和良好的耦合平坦度。该方法提高了耦合孔尺寸和位置的精度,减小了反射损耗,为太赫兹波导结构的加工提供了新思路。     

Compact duplexer-polarizer with semicircular waveguide [antennafeed]

A light, compact, and high-performance duplexer-polarizer able to generate circularly polarized waves in a circular waveguide is discussed. Two prototypes were built. The standing-wave-ratio (SWR) and ellipticity performances are extremely good (less than 0.15 dB ellipticity over 15% bandwidth). The experimental development was facilitated by the computation of the dispersion curves and of the transverse field distribution associated with the two fundamental guided modes propagating in the different sections of a septum waveguide     

A simple circular-to-rectangular waveguide transition

We describe a novel one-step TE/sub 11/-mode circular waveguide to TE/sub 10/-mode rectangular waveguide transition. The primary advantage of this device over existing transitions is its ease of fabrication. We have incorporated our transition into a number of waveguide components operating at V-band. The transition's measured return loss exceeds 15 dB over a 12% bandwidth centered near 60 GHz.     

Broadband, electrically long vertical waveguide interconnect

A bandwidth optimised vertical interconnect using a rectangular waveguide to couple two microstrip lines is presented. The electrically long interconnect gives low insertion loss and large bandwidth, in contrast to other indirectly and directly coupled interconnects. Experimental results show <1.5 dB insertion loss and <20 dB return loss over a wide bandwidth 8.1-0.7 GHz     

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.     

W波段宽带SIW背腔缝隙天线

W波段（75~110 GHz）的电磁波大气吸收率低、波长短、可用频带宽,在雷达、通信等领域应用广泛.文章设计了一种W波段基片集成波导（substrate integrated waveguide,SIW）背腔缝隙天线,-10 dB的阻抗带宽达到28.6%（78.93~105.24 GHz）,覆盖了W波段75%的频带范围.天线采用双层基片结构.上层为SIW谐振腔及四条辐射缝隙构成的谐振辐射单元,谐振腔内同时存在TM₁₃₀与TM₃₁₀混合模、TM₃₂₀模以及TM₃₃₀模三种高次模,和辐射缝隙一起形成多谐特性,实现带宽拓展;底层为通过耦合缝隙馈电的集成波导,易于扩展成平面网络,构建高增益背腔缝隙天线阵列.该天线频带宽、交叉极化低、剖面低、易于与平面微波电路集成、加工成本低,具有良好的应用前景.     

Monolithic InGaAs photodiode array illuminated through an integrated waveguide

A linear array of InGaAs PIN photodiodes has been fabricated which can be illuminated through a slab waveguide from the opposite side of the InP substrate via total reflection at a V-groove mirror. Absorption losses in the double-heterostructure waveguide are 2.5 dB/cm. The internal quantum efficiency of the photodiodes, including the mirror loss, is 87%, and an optical crosstalk between the diodes better than ?40 dB was measured.     

Circularly polarized dielectric-loaded planar antenna excited bythe parallel feeding waveguide network

A new receiving planar array antenna for DBS (direct broadcasting satellite) is proposed. The element antenna is a short waveguide aperture mounted in the ground plane, loaded with a dielectric and polarizers, and excited through its side wall by another feeding rectangular waveguide. The gain of the element antenna loaded with a dielectric is so high that the grating lobes can be reduced sufficiently even if the element spacing in the array is wider than the wavelength in free space. Therefore we can reduce the number of the array elements, and parallel feeding by the low loss waveguide network can be feasible to provide a planar array antenna. This paper describes the experimental results of several kinds of the circularly polarized dielectric-loaded element antennas and the planar antennas fed by the waveguide network. In the 12 GHz band the planar antenna with 64-element radiators has a maximum gain of 31.9 dBi with an aperture efficiency of 94.7%, the 1 dB-down frequency bandwidth of the gain is about 800 MHz (6.7% for a center frequency of 11.85 GHz), and the frequency bandwidth of the axial ratio is less than 1 dB of 850 MHz (7.2%)     

毫米波车地通信的小型化波导螺旋阵列天线设计

高速磁浮列车毫米波车地通信系统要求其车载天线具有小型化、宽频带、圆极化和辐射扇形波束等特点。为更好地满足这些要求,设计一种中心馈电的小型化波导螺旋阵列天线。该天线馈电系统采用同轴波导中心馈电、4路矩形波导并馈的形式,通过改变馈电波导尺寸、耦合探针长度以及末端采用波导同轴转换器等形式,实现了所有单元的等幅馈电;天线单元由低剖面螺旋天线构成,采用顺序旋转技术改善天线的圆极化性能。利用全波电磁仿真软件设计了一款中心频率为38 GHz的28单元波导螺旋阵列天线,并进行了实验测试。测试结果表明：在37~39 GHz频带范围内,天线驻波比小于1.41,增益大于21.7 dB,轴比小于3.6 dB,俯仰面波瓣宽度为4.5°~4.7°,方位面波瓣宽度为29°~29.7°,满足毫米波车地通信系统车载天线的设计需求。     

Arrayed waveguide lens wavelength add-drop in silica

We present experimental results of an integrated 16-channel, 100-GHz-channel-spacing wavelength add-drop in silica. It consists of two interleave-chirped waveguide grating routers connected by an array of waveguides containing thermooptic phase shifters. The fully packaged device has 6.6-7.6-dB fiber-to-fiber insertion loss and a switching extinction ratio >27 dB (>33 dB for a single polarization) when used as an add-drop, It is compact, allowing for at least four such devices per 5-in-diameter wafer