Ka波段相位平衡式镜频抑制混频器的设计

Design of Ka-Band Phase Balanced Image Rejection Mixer

为了提高毫米波外差式接收机抗干扰能力,本文利用ADS仿真设计了Ka波段镜频抑制混频器。该混频器采用Hartley结构,利用输出信号的相位关系识别有用信号和镜频信号,有用混频信号在输出端口同相叠加,镜频混频信号反相抵消。ADS仿真结果表明:在频段34-36GHz,变频损耗小于9.5d B,信号与本振隔离度大于10d B,中心频率处大于25d B,镜频抑制度大于25d B,本振与信号端口驻波小于1.35。

In order to improve the ability of anti-interference of heterodyne receiver in Ka band, a Ka band image rejection mixer is simulated and designed. The mixer adopts Hartley structure, and the useful signal and image signal can be distinguished by the phase relationship of the outputs from two single balanced mixing units. The useful signal outputs of the two units are in-phase, while the image signal outputs are 180 phase difference and offset. The ADS simulated result shows that, in the range of 34~36GHz, the conversion loss is less than 9.5d B, the image rejection is larger than 25 d B, the isolation between LO port and RF port is better than 10 d B, even greater than 25 d B at the centre frequency, the voltage standing wave ratio of the RF and LO ports are less than 1.35. Finally the simulation results better meet the design requirements.