基于CMOS工艺的150 GHz正交外差探测器电路设计

传统太赫兹探测器仅能获取信号幅值信息，为此提出一种正交外差混频结构，可同时获得信号的幅值、相位和极化信息，有效提升探测器的灵敏度和信息量。该探测器基于40 nm互补金属氧化物半导体(CMOS)工艺，在传统吉尔伯特双平衡混频结构的开关级与跨导级之间串联电感，输出级联cascode中频放大器，进一步提高探测器响应电压。经过仿真优化，该探测器在 -50 dBm射频功率，0 dBm本振功率条件下，1 GHz中频信号的电压响应度为1 100 kV/W，噪声等效功率为26.8 fW/Hz^1/2，输出波形显示了良好的正交性。同时，设计了一个1∶8层叠式功分器用于分配本振功率，在150 GHz频率处，该功分器的插入损耗约为5 dB，四路差分输出信号的幅值差为0.8~1.2 dB，相位差为0.4°~1.7°。

Design of 150 GHz quadrature heterodyne detector circuit in CMOS

The traditional terahertz detector can only obtain the amplitude of signal. An orthogonal heterodyne mixing structure is presented, which can obtain the amplitude, phase and polarization information at the same time, and effectively improves the sensitivity and information of the detector. Based on 40 nm Complementary Metal Oxide Semiconductor(CMOS) process, the detector connects the inductors in series between the switch stage and the transconductance stage of the traditional Gilbert double balanced mixer structure. The cascode IF(Intermediate Frequency) amplifiers are cascaded to further improve the response voltage of the detector. After simulation and optimization, the voltage responsivity of 1 GHz IF signal is 1 100 kV/W and the noise equivalent power is 26.8 fW/Hz^1/2 under the condition of -50 dBm RF(Radio Frequency) power and 0 dBm LO(Local Oscillation) power. The output waveform shows good orthogonality. Meanwhile, a 1:8 power divider is designed to distribute the LO power. The insertion loss of the power divider is about 5 dB at 150 GHz. The amplitude difference of four-differential-output is 0.8~1.2 dB, and the phase difference is 0.4°~1.7°.