一种新型宽带平面和差网络

提出了一种新型的基于环形电桥结构的宽带平面和差网络。首先提出了一种新型的宽带微带/槽线转换结构,然后将该结构引入到传统的环形电桥结构中,优化设计了一种改进型环形电桥,最后采用四个改进的环形电桥构建了双平面和差网络。测试结果表明:在4.05～7.425GHz的频率范围内,八个端口的驻波均小于2,输入端口之间的隔离度均在20dB以上,输出端口之间的隔离度大于30dB,和端口的插入损耗小于0.5dB,差端口的零值深度小于-30dB。该和差网络具有性能优良、结构简单、制作成本低等优点,在宽频带单脉冲雷达天馈系统中得到了成功的应用。     

新型3 dB电桥的设计

针对450 MHz频段通信系统中3 dB电桥体积过大的情况,基于微波网络理论提出了一种方形微带线3 dB电桥实现方案.借助Agilent公司的ADS(Advanced Design System)软件完成了仿真设计,通过其内嵌的LAYOUT工具并结合PADS LAYOUT软件,设计制作了PCB版电路.实测结果接近仿真数据,各端口回波损耗低于-20 dB,端口间隔离小于-30 dB,均满足450 MHz中频、20 MHz带宽前馈线性功放模组的要求,而其版图面积只有传统环形电桥版图面积的8%.     

波导带通滤波器与微带转换装置的设计

利用三维仿真软件HFSS首先设计了K波段7阶电感E面带通波导滤波器,以及波导-微带转换器.其中波导滤波器的中心频率为19 GHz,带宽为3 GHz,带内损耗小于0.1 dB,端口反射小于-20 dB;而波导-微带的转换器在16～20.8 GHz的带宽内端口反射小于-20 dB,带内损耗小于0.1 dB.然后将两者有效结合为一体,其工作带宽为17.5～20.5 GHz,带内损耗为0.3 dB,端口反射小于-15 dB,带外抑制小于-30 dB,可以满足实际系统应用的需求.     

一种新型毫米波8路功分器/合成器的设计

设计了一种Q波段8路功分器/合成器。利用波导功分器及微带功分器混合设计,提出了波导-微带4路功分器与3 dB Wilkinson电桥一体化设计思想,设计出一种较高隔离度,结构紧凑的新型8路功率分配器/合成器。通过高频电磁仿真软件(HFSS)仿真设计,在42 GHz~47 GHz频带范围内,8路分配器输出端口反射损耗优于-19 dB;8路输出端口的幅度不平衡度小于0.25 dB,相位不平衡度小于0.5o,插损小于0.25 dB;4个输出口之间的隔离度大于9 dB,是一种较为理想的8路功率分配器/合成器,在实际小体积高合成效率要求的固态功率合成领域,以及具有小体积的多路信道实现中,具有较高的应用价值。     

W 波段单平衡混频器的设计

本文设计并制作了一种微带形式W 波段单平衡混频器。该混频器采用微带环形电桥结构,射频和本振信号分别从环形电桥的隔离端口由标准波导BJ-900 输入,经对脊鳍线微带波导过渡输入到微带电路,中频信号通过跳线方式连接并通过一段高阻抗线引出到输出口。该电路使用两只DMK2790 肖特基二极管制作在介电常数为2.2,厚度为0.127mm 的RT/Duriod5880 基片上,在固定本振94.5GHz,射频90GHz 到98GHz 范围内,变频损耗小于14.5dB。     

一种新型宽带环形电桥耦合器设计

传统四端口环形电桥耦合器的带宽只有10%到20%。为了获得更大的带宽,本文提出了一种改进型环形电桥耦 合器。通过额外增加一个隔离臂,新设计可以工作在整个W波段。在此基础上,本文在输入臂上加入了一个切角来改善 输出信号的隔离度。仿真研究结果表明,在75GHz 到110GHz,两输出信号的幅度不平衡度小于0.07dB,相位不平衡度小 于0.37 度。相比于未作切角处理的五端口环形电桥,新设计输出端口的隔离度在全频段内大于15.07dB。改进型耦合器 可以应用于W波段平衡调制器以及其他需要高输出隔离度的W波段功率分配系统。     

宽带混频器的优化设计

采用0.25μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺设计并实现了一款单片宽带混频器.该混频器采用双平衡混频器结构,以串联的两个漏源相连的PHEMT作为环形二极管电桥中的二极管以提升混频器线性度.本振巴伦和射频巴伦均采用螺旋线式Marchand巴伦,为降低巴伦的幅度及相位不平衡度,采用遗传算法对巴伦的几何参数进行了优化设计.该混频器电路采用0.25 μm GaAs PHEMT工艺实现,芯片面积为1.5mm×1.1 mm.测试结果表明,当本振功率为20 dBm时,变频损耗小于7 dB,输入三阶交调点ⅡP3大于22 dBm.本振端口到射频端口和中频端口的隔离度均大于30 dB.     

基于微带双脊间隙波导技术的Ka波段六端口网络电路

面向毫米波高精度雷达探测应用,文中提出了一种基于微带双脊间隙波导技术的六端口网络电路。设计了基 于微带双脊间隙波导的功分器和耦合器电路,提出了微带双脊间隙波导至微带线的新型过渡转换结构,并基于简化的六 端口网络原理框图,将所设计的功分器、耦合器以及过渡转换结构进行有机组合,实现了所设计的Ka 波段六端口网络电 路。实验测试结果表明:在所设计的37.5 GHz~ 42.5 GHz 频率范围内,输入端口1 与四个输出端口间的相位差均 在±2.5°以内,输入端口2与四个输出端口间的相位差均在±5°内,工作中心频率处的输入输出间插入损耗约为7.3 dB。 实验与仿真结果吻合较好。     

K波段单平衡上变频器的设计

文中介绍了一种应用于宽带无线接入系统发射机的K波段单平衡上变频器的设计方法,并给出了仿真结果和电路版图。电路选用Alpha公司的砷化镓肖特基势垒二极管,采用易于实现的环形电桥结构。通过在环形电桥的一个端口附加45。相移实现了上边带单平衡混频,变频损耗小于6dB,三阶交调系数为39dB,输入1dB压缩点为10dBm。整个电路具有低成本、低变频损耗的特点。     

X波段8路波导功分器/合成器

波导结构具有传输损耗低、功率容量大的特点。本文提出了一种基于波导结构功分器/合成器设计方法,并利用CST2014软件设计了一款X波段8路波导功分器/合成器。仿真与测试都显示其性能良好,在整个X波段插损小于0.05dB,反射损耗大于15dB,中间大部分频段(8.8~12.2GHz)反射损耗优于20dB。     

Four-channel wavelength division multiplexers and bandpass filtersbased on elliptical Bragg reflectors

Four-channel multiplexers and four-wavelength bandpass filters based on elliptical Bragg reflectors (EBRs) are discussed. The channel spacing is 50 Å near 1.56 μm. The EBRs are narrowband elliptical mirrors that can refocus light from an input waveguide to any one of a number of output waveguides. Spectrally, they perform similarly to Bragg reflectors. The devices were fabricated on silicon using silica-based waveguide technology. The elliptical gratings with 0.53-μm periods were patterned using deep UV spatial frequency doubling photolithography. Multiplexers with single filtering and double filtering were demonstrated. With single filtering, the fiber-to-fiber insertion loss was 3.0±0.5 dB, and the crosstalk was -20 dB; with double filtering, the insertion loss was 4.0±0.5 dB, and the crosstalk was -30 dB. About 2 dB of this loss was due to coupling between the fibers and the waveguide. The additive loss associated with the EBR, including propagation, Bragg reflection, and coupling between input and output waveguides, was about 1 dB     

A Ku-BAND WAVEGUIDE FREQUENCY MULTIPLIER USING HARMONIC-REJECTION MICROSTRIP PATCH TRANSITIONS

A compact frequency multiplier waveguide module is built by placing a planar microstrip section between two rectangular waveguides. The size of the microstrip section is minimized by eliminating all harmonic band-rejection filters. Special feed locations for the input waveguide-to-microstrip transition patches provide the second-harmonic rejection at the input, and a balanced circuit configuration formed with a pair of transistors produces the pump signal cancellation at the output. The measurements on a fully-assembled waveguide module showed a peak frequency conversion gain of-2.3 dB at 16.7 GHz with the associated output power level of 6 dBm.     

A Novel Terahertz Rat-Race Hybrid Coupler Based on PPDW

A novel rat-race hybrid coupler based on parallel-plate dielectric waveguide (PPDW) is proposed. PPDW has been proposed as a basic terahertz transmission line for its remarkable simple structure and comparatively low attenuation at terahertz frequency band. It can be applied to design many terahertz components. In this paper, a (3 N + 3/2) × lambda circumference PPDW rat-race hybrid coupler operating at quasi-TE₁₀ mode is studied. The investigation results show that, at 0.34 THz, the transmission losses of the two split output ports are both equals −3.2 dB; the return loss at its input port is below −20 dB; the insertion loss at each split transmission port is less than 0.2 dB; and the two isolated ports show good isolation of above 20 dB. Therefore, it will have wide potential applications at terahertz frequency band.     

高隔离度Ka波段平面魔T的设计

提出了一种适合于毫米波微波集成电路(M IC)的高隔离度平面魔T结构,该结构属于一种新型的180°平面型混合网络。基于传统的微带混合环原理,引入了微带-槽线过渡的结构,两个端口之间的180°相移通过微带-槽线转换结构实现,从而实现了输出端口的隔离。该结构采用多节阻抗匹配网络,增加了工作带宽,使微带-槽线过渡结的寄生耦合最小化。通过设计可实现得到最小尺寸的槽线终端,降低了微带-槽线过渡结的辐射损耗。引入的等效电路模型有效地提高了平面魔T的设计。借助CST软件,仿真优化了λg/4变换器以及微带-槽线转换结构的阻抗匹配,提高了隔离度。实验结果表明:在工作带宽(34～36 GHz)内,该结构输出端口2和3的隔离度达20 dB,输入端口回波损耗低于18 dB,插入损耗1 dB。     

18GHz场效应放大器的实用设计

本文叙述在17.5～18GHz频带工作的低噪声场效应晶体管放大器之实用设计及其性能.放大器包括三级级联微带放大电路和波导输入/输出端口,获得了4.5dB的噪声系数和17dB的总增益.     

Ultra-Wideband Power Divider With Good In-Band Splitting and Isolation Performances

An ultra-wideband (UWB) power divider on microstrip line is proposed, analyzed and designed. This divider is formed by installing a pair of stepped-impedance open-circuited stubs and parallel-coupled lines to two symmetrical output ports. In addition, a single resistor is properly placed between two output ports. After simple transmission line theory analysis, it is demonstrated that 3 dB power splitting from one input to two output ports, good impedance matching at all the three ports and excellent isolation between two output ports are achieved over the specified 3.1–10.6 GHz UWB range. Finally, a prototype divider is fabricated and measured to provide an experimental verification on the predicted attractive features.      

Polymer-based 1 /spl times/ 6 thermooptic switch incorporating an elliptic TIR waveguide mirror

A polymeric 1 /spl times/ 6 thermooptic switch is fabricated and demonstrated. The device utilizes an elliptic total internal reflection waveguide mirror imaging the input channel waveguide onto the first output channel waveguide and a prism-array heating electrode steering the beam to corresponding output channel waveguides. At 1310 nm, 1 /spl times/ 6 switching was demonstrated; the extinction ratios and crosstalks were found to be >20 and -20 dB, respectively. Switching time as low as 4 ms was observed. The device offers the advantage of a single-electrode driving scheme for 1/spl times/N(N>2) switching.     

基于左手传输线的宽带巴伦设计

提出了一种基于左手传输线的新型Wilkinson巴伦,该巴伦由一个Wilkinson功分器和两条相位响应相差180°的相移 线构成,它具有结构紧凑和宽频带的特点。采用陶瓷基板薄膜加工工艺,制作了一个工作于C波段的Wilkinson巴伦。最后 测试结果显示：从4GHz到6GHz的频率范围内,输入端反射系数|S11|和输出端隔离|S23|均小于-15dB,两输出端口幅度和相 位不平衡性小于0.3dB和±2°,输出端插入损耗|S21|和|S31|大于-4dB。     

Perturbation analysis and modeling of curved microstrip bends

The curved microstrip bend consisting of a microstrip ring segment between two microstrip lines is analyzed for its transmission properties. The microstrip lines are modeled by equivalent ideal magnetic wall waveguides for which the electromagnetic field solutions are known. The field solutions in the microstrip ring segment are derived by using a perturbation analysis of a modified (magnetic wall) curved waveguide model. Other techniques have been formulated to evaluate the fields inside curved metallic waveguides. These include the use of an equivalent nonuniformly loaded straight waveguide and rectangular and annular model analysis. The perturbation solution for the fields in the equivalent curved waveguide model presented is readily adaptable to the mode-matching procedure, and is used to calculate the properties of the curved microstrip bend discontinuities. The frequency-dependent reflection and transmission coefficients of curved microstrip bends are determined and compared with those of the right-angle and chamfered right-angle microstrip bends