Design and fabrication of MMW module for 94 GHz radar sensor applications

We present design and fabrication of a 94 GHz radar sensor module. The 94 GHz sensor module has four components including 94 GHz single balanced diode mixer part, waveguide VCO (voltage controlled oscillator) part, magic tee part and bias PCB part. The 94 GHz single balanced diode mixer is developed on Duroid RT 5880 substrate with DC 1346 Schottky diode. The mixer has advantage of good conversion loss at high LO power and isolation characteristic. 94 GHz single balanced diode mixer has advantage of comparatively easy fabrication. The waveguide VCO consist of GaAs Gunn diode, varactor diode, two-bias post and cavity. The waveguide VCO is operated at 94 GHz. The magic tee has four waveguide arm regions with standard WR-10 and divides output power from VCO. Transmission frequency of 94 GHz MMW sensor module is 93.607 ~ 94.727 GHz. Bandwidth is 1.12 GHz. 2% linearity range is 680 MHz. Power is 11.03 ~ 11.47 dBm. Conversion loss about -7 dB at IF 500 MHz.