660-GHz频段波导型SIS混频器嵌入阻抗的特性研究(英文)

INVESTIGATION OF EMBEDDING IMPEDANCE CHARACTERISTIC FOR A 660-GHZ WAVEGUIDE SIS MIXER

基于三维电磁场仿真软件HFSS和类似于准光学天线的集总源法 ,对一 6 6 0GHz超导混频器的嵌入阻抗在整个 6 0 0 72 0GHz的工作频带范围内进行了详细的分析研究 .同时 ,还系统地分析计算了SIS结芯片的馈点偏移(包括水平偏移和垂直偏移 )及芯片厚度和背向短路器长度变化所产生的影响 .分析结果表明 ,该混频器的嵌入阻抗为 35Ω左右 ,而且在整个工作频带内变化缓慢 ,能够实现宽频带匹配 .SIS结芯片馈点的位置对嵌入阻抗没有太大的影响 ,但芯片厚度的影响非常明显 .这些结果对超导SIS混频器的研制有很好的指导意义 .

With the help of an electromagnetic field simulator (i.e., HFSS) and a lumped-gap source method similar to the quasi-optical antennas, the embedding impedance of a 660-GHz waveguide SIS (Superconductor-Insulator-Superconductor) mixer was thoroughly investigated from 600 to 720 GHz. The effects of the junction's feed-point displacement( including horizontal and vertical offsets), chip thickness and backshort length were analyzed and calculated. The results indicate that the simulated embedding impedance of the mixer is-around 35Omega over the working frequency range, which can match the SIS junction in a large bandwidth. The feed point location of the SIS chip has little effect on the embedding impedance., while the chip thickness obviously does. These results will benefit the development of waveguide SIS mixers.