330 GHz高性能二次谐波混频器设计

采用反向并联肖特基二极管对设计了一种330 GHz二次谐波混频器。混频器电路采用微带结构,使用波导-微带探针耦合的形式进行过渡;采用50 μm厚的石英作为基板,有效减小了电路体积;采用HFSS和ADS对电路进行仿真和谐波平衡仿真。仿真结果显示,混频器在310~350 GHz范围内的变频损耗优于9.5 dB,所需本振(LO)功率为3 dBm,有效降低了对本振的要求。     

基于肖特基二极管的670 GHz四次谐波混频器设计

常温固态太赫兹谐波混频器是太赫兹系统应用中的关键器件。介绍了一款基于肖特基二极管的670 GHz四次谐波混频器的仿真与设计。在高频结构仿真软件(HFSS)中对准垂直结构肖特基势垒变阻二极管进行三维结构建模,采用基于谐波平衡算法的整体综合仿真方法对混频器进行仿真和优化。结果表明：在功率为10 mW的167 GHz本振信号驱动下,混频器单边带变频损耗在637~697 GHz射频频率范围内小于13.8 dB,3 dB变频损耗带宽为60 GHz;最优单边带变频损耗在679 GHz为10.6 dB。     

3mm波段四次谐波混频器阵的研究

采用微带结构研制出3毫米波段8路四次谐波混频器阵。该混频器核心器件采用型号为MS8251的GaAs梁式引线肖特基势垒二极管对。设计了一种便于组阵结构的四次谐波混频器,把混频器分解为反向二极管对模块和双工器模块。反向二极管对模块和双工器模块电路分别设计和安装在厚度为0.127mm和0.254mm的RT/Duriod 5880基片上。实测混频器的最低变频损耗为17dB。     

340 GHz固定调谐分谐波混频器

基于最新研制的小阳极结反向并联肖特基二极管芯片,设计和制造了320~360 GHz固定调谐分谐波混频器。混频器的结构采用的是传统电场（E）面腔体剖分式结构:将二极管芯片倒装焊粘在石英基片上,再用导电银胶将石英电路悬置粘结在混频器下半个腔体上。电路设计采用场路相结合的方法:用场仿真软件建立混频电路各个功能单元的S参数模型,将它们代入非线性电路仿真软件中与二极管结相结合进行混频器性能整体仿真优化。最终测试结果表明,谐波混频器的双边带在4~6 mW的本振功率驱动下,在320~360 GHz超过12%带宽范围内,双边带变频损耗均小于9 dB;混频器在310~340 GHz频带范围内,双边带噪声温度最低为780 K。声温度最低为780 K。     

330 GHz太赫兹次谐波混频器设计

为了缓解微波频段频谱资源的日益紧张,对太赫兹频段进行探索,介绍了一款基于GaAs肖特基二极管的330 GHz次谐波混频器。设计采用了整体综合设计的方法,进行高频结构模拟器(HFSS)与先进设计系统(ADS)联合仿真。优化过程中,电路不连续性通过HFSS仿真结果表征,电路传输特性和二极管非线性特性由ADS仿真结果表征,通过优化传输线参数,实现优化电路的目的。此方法增大了仿真优化空间,降低了设计难度。仿真结果显示,在300~350 GHz频段内,混频器的变频损耗小于8 dB。     

0.67 THz宽带谐波混频器设计

为研制太赫兹多频段高灵敏度探测仪,依靠太赫兹砷化镓平面肖特基二极管的非线性特性,结合石英薄膜工艺,设计了宽带0.67 THz谐波混频器,并分析了砷化镓平面肖特基二极管性能表征参数指标对太赫兹混频器性能的影响。0.67 THz谐波混频器采用整体综合的设计方法,结合电气仿真软件ADS和电磁仿真软件HFSS,优化电路中不连续性微带与波导之间的电磁空间耦合效率,以混频器的变频损耗为优化目标,最终实现0.67 THz谐波混频器仿真设计。0.62~ 0.72 THz射频范围内,混频器单边带最低变频损耗小于8 dB,本振功率小于4 mW,本振端口与中频端口、射频端口与中频端口之间隔离度大于-30 dB。     

基于平面肖特基二极管的毫米波固定调节式谐波混频器

基于GaAs肖特基势垒二极管,研制出了两个不同波段的谐波混频器。在场仿真软件中,二极管的非线性结采用lumped端口来模拟,通过场分析方法分析二极管各端口的阻抗。谐波混频电路被分成不同部分来单独优化设计,基于优化设计的各独立电路,建立谐波混频器的整体场仿真模型,通过提取相应的S参数文件分析混频器的变频损耗。150GHz 谐波混频器测得最低变频损耗10.7dB,在135-165GHz变频损耗典型值为12.5dB。180GHz 谐波混频器测得最低变频损耗5.8dB,在165-200GHz变频损耗典型值为13.5dB,在210-240GHz变频损耗典型值为11.5dB。     

基于肖特基二极管改进模型的W波段宽带八次谐波混频器

在对肖特基二极管电磁模型和电路模型精确建模的基础上,设计并制作了W波段宽带八次谐波混频器.通过对肖特基二极管物理结构的分析,建立了其精确的三维电磁仿真模型和直到180 GHz的改进的宽带等效电路模型.针对W波段八次谐波混频器混频产物能量分布特点和工作带宽要求,设计了宽带射频和本振匹配网络,使混频器的工作带宽能覆盖整个W波段.测试结果显示,射频信号在75~110 GHz频率范围内,W波段八次谐波混频器最大变频损耗28 d B,最小变频损耗18 d B.     

基于石英基片的二毫米波段二次谐波混频器设计和研制

介绍了一种基于石英基片的2mm波段二次谐波混频器.阐述了谐波混频器的基本原理,建立了混频二极管对结构的高频模型,并用全波分析软件对整个电路进行了仿真优化.实测得到射频信号在116～120GHz范围内,当本振频率为59GHz、功率为7～14dBm时,最低变频损耗为17dB,最高变频损耗为20dB.混频器的P1dB为1dB...     

星载220 GHz分谐波混频器设计

为满足星载辐射计系统应用,提出了一款220 GHz次谐波混频器。基于平面GaAs肖特基二极管3D电磁模型,混频器电路和结构优化设计采用HFSS和ADS联合仿真实现。通过在50μm厚的石英基板上倒装反向并联二极管对以及采用纳米银胶将基板粘接在硅铝波导腔的工艺方式,设计并加工实现了一款210～240 GHz分谐波混频器,单边带最小变频损耗仿真结果为7.33 dB,实测变频损耗优于9.6 dB。按照某卫星规定的各项环境试验条件验证其在不同环境条件下的性能,结果证明该混频器试验前后一致性较好。     

5 THz混频二极管等效电路模型研究

采用电磁场和电路联合仿真,基于直流测试和三维电磁建模仿真技术,建立了截止频率5 THz的混频肖特基二极管的等效电路模型。重点研究了二极管的非线性结模型和外围结构三维电磁全波仿真模型,构建了考虑实际电路形式的四端口三维电磁全波仿真模型。该等效电路模型可用于太赫兹低频段混频模块设计,该模型的建立方法也为更高频段模型的建立提供了一种参考。基于该模型设计了一款220 GHz分谐波混频器,在192~230 GHz宽带范围内,双边带变频损耗小于10 dB,测试结果与仿真结果较为一致。     

A low-noise fixed-tuned 300-360-GHz sub-harmonic mixer using planar Schottky diodes

This letter presents the design and fabrication of a low-noise fixed-tuned 300-360-GHz sub-harmonic mixer, featuring an anti-parallel pair of planar Schottky diodes fabricated by the University of Virginia and flip-chipped onto a suspended quartz-based microstrip circuit. The mixer exhibits a double side band (DSB) equivalent noise temperature lower than 900K over 18% of bandwidth (300-360-GHz), with 2 to 4.5mW of local oscillator (LO) power. At room temperature, a minimum DSB mixer noise temperature of 700K and conversion losses of 6.3dB are measured at 330GHz.     

基于Schottky二极管和Hammer-Head滤波器0.67 THz二次谐波混频器

通过测量肖特基二极管的I-V和C-V曲线,建立等效电路模型.利用三维电磁场和谐波平衡仿真工具分别进行三维结构仿真和电路宽带匹配,最终实现混合集成方式的0.67THz谐波混频器设计.测试结果表明:混频器中心频率为0.685 THz,射频3 dB带宽为47 GHz,双边带变频损耗13.1~16 dB,在685 GHz双边带噪声温度最低值为11500 K.     

A Simple Method for Millimeter-Wave Finline Balanced Mixer Design Using Three-Dimensional Field Simulation Software

In this paper, a simple method for millimeter-wave finline balanced mixer design using three-dimensional field simulation software has been proposed. The method can be widely used to design the diode-based circuits, especially for the circuit structures with orthogonal field in some specific hybrid integrated circuits which are unavailable to be designed using the circuit simulator. In these circuits, the power directly at diodes is correlated to the input reflection coefficient. The diodes mounted on the finline circuits are defined as impedance boundary in the commercial computer-aided design (CAD) tool High Frequency Structure Simulator (HFSS) model, and hence simulation with the use of HFSS can be implemented to optimize the input matching network of the finline circuits for transferring maximum power to the diodes. Two finline balanced mixers at U-band using commercial GaAs Schottky diodes have been designed and fabricated to validate this method. Matching structures at the radio frequency (RF) port have been employed for a better return loss and a lower conversion loss. Experiment results are presented and show good agreement with simulation data. The proposed method has proven to be useful for the design of millimeter-wave mixers in finline technique.     

Robust Sub-harmonic Mixer at 340 GHz Using Intrinsic Resonances of Hammer-Head Filter and Improved Diode Model

This paper presents a sub-harmonic mixer at 340 GHz based on anti-parallel Schottky diodes (SBDs). Intrinsic resonances in low-pass hammer-head filter have been adopted to enhance the isolation for different harmonic components, while greatly minimizing the transmission loss. The application of new DC grounding structure, impedance matching structure, and suspended micro-strip mitigates the negative influences of fabrication errors from metal cavity, quartz substrate, and micro-assembly. An improved lumped element equivalent circuit model of SBDs guarantees the accuracy of simulation, which takes current-voltage (I/V) behavior, capacitance-voltage (C/V) behavior, carrier velocity saturation, DC series resistor, plasma resonance, skin effect, and four kinds of noise generation mechanisms into consideration thoroughly. The measurement indicates that with local oscillating signal of 2 mW, the lowest double sideband conversion loss is 5.5 dB at 339 GHz; the corresponding DSB noise temperature is 757 K. The 3 dB bandwidth of conversion loss is 50 GHz from 317 to 367 GHz.     

Schottky-Barrier Diodes for Submillimeter Heterodyne Detection

The fabrication and packaging techniques which were used to produce high-reliability mixer diodes for millimeter-wave satellite communications systems have been extended to produce Schottky-barrier mixer diodes for use in the submillimeter-wave region from 1 to 0.1 mm. The influence of material and circuit parameters on the performance of Schottky-barrier diodes as heterodyne detectors in the submillimeter-wave region has been considered. The semiconductor material parameters have been optimized and new packaging concepts have been investigated. A new diode package has been developed which incorporates both an integral stripline filter on 0.05-mm-thick quartz and a section of overmoded waveguide. The new package has the advantage of being replaceable in the mixer circuits, and yet it can provide a low-loss interface between the diode package and the mixer circuit. A new surface-oriented device has been developed in which the contact to the Schottky barrier is formed by photolithographic techniques onto the same surface as the ohmic contact. The surface-oriented devices exhibited heterodyne detection into the submillimeter region.     

A 77 GHz SiGe sub-harmonic balanced mixer

A novel SiGe 77 GHz sub-harmonic balanced mixer is presented with a goal to push the technology to its limit [SiGe2-RF transistor (f/sub T/=80 GHz)]. This new topology uses a compact input network not only to achieve high isolation between the LO and RF ports, but also to result in excellent 2LO-RF isolation. The measured results demonstrate a conversion gain of 0.7 dB at 77 GHz with an LO power of 10 dBm at 38 GHz, LO-RF isolation better than 30 dB, 2LO-RF isolation of 25 dB, and a P/sub 1dB/ of -8 dBm. The mixer core consumes 4.4 mA at 5 V. The circuit demonstrates that SiGe sub-harmonic mixers have comparable performance with GaAs designs, at a fraction of the cost.