U-band Mixer Technology

During the microwave-millimeterwave telemetry system and transceiver system, mixers were the vital component. The U band was in the atmospheric attenuation band, so this mixer could be used in the secure communication. In the millimeter wave band, the study of mixers was the important project of the millimeter technology. This thesis introduced a design project of U band millimeter mixer, which was simulated, fabricated and tested.According to the project, the thesis designed a single-balanced mixer. The structure was formed of finline and suspended micro-stripe. Finline and suspended micro-stripe made up 180 degree knot, which was the basement of mixers. Meantime, two diodes was placed in the finline and suspended micro-stripe. The electric fields of finline and suspended micro-stripe were orthogonal. The power of LO port passed the waveguide and the waveguide-microstrip probe structure, after the power passed the LO filter to two diodes. Power of RF passed the waveguide-finline structure to two diodes too. The IF power passed the lowpass filter to export. During the place of two diodes, we used round angle structure to connect finline and suspended micro-stripe.After the mixer was fabricated, we tested it. During the acquired frequencies, the conversion losses were less than 6.7 dB, and the minimum value is 5.2 dB. The isolation of LO-RF was more than 25 dB, and the isolation of LO-IF was more than 35dB. The P1dB of RF port was more than 8 dBm, and the bandwidth of IF was about 10GHz.