设计了一种宽带低损耗交叉杆式单平衡混频器。理论分析了单平衡混频器的三种拓扑结构,根据分析结果选择器件的架构。在射频端将二极管直接安装在减高后的波导传输线上,实现二极管与传输线的宽带匹配,同时规避了平面传输线的损耗。本振和中频端均采用微带线(非平衡传输线)作为馈线,易与其他平面结构相互集成。波导过渡结构、本振带通滤波器和中频低通滤波器覆盖整个W波段(75~110 GHz),以保证混频器的宽带特性。测试结果表明,在中频100 MHz时,整个W波段内混频器的单边带变频损耗为(5±0.5) dB。

In this paper, a broadband crossbar single balanced mixer with low conversion loss is proposed. First, based on the analysis of three topologies, the single balanced structure is chosen. At the radio frequency (RF) port, the diodes are mounted on the height-reduced waveguide to achieve the broadband matching between the diodes and the transmission line and avoid the loss of the planar transmission line. Furthermore, microstrip unbalanced transmission lines, which can be easily integrated with other planar structures, are adopted as feeding lines at the local oscillator (LO) port and the intermediate frequency (IF) port. To ensure the wideband performance of the mixer, the waveguide transition, the LO band pass filter, and the IF low pass filter are designed to cover the full W-band (75-110 GHz). The test results show that with a 100 MHz for IF, the single-sideband conversion loss of the mixer is (5±0.5) dB in the whole W-band.