Third Millimeter-wave Electromagnetic Properties Measurement Radar Front End

The millimeter-wave front-end is one of the most important parts of the millimeter-wave radar. The development and the applications of the millimeter-wave radar are limited by the level of the millimeter-wave circuits and devices. The front-ends of the 3mm electromagnetism characteristic measurement radar are the most important component of the electromagnetism characteristic measurement equipments. In this paper, the 3mm electromagnetism characteristic measurement radar consists of radiation measurement system and RCS measurement system. And, the front-ends of radar consist of the radiometer front-end, the RCS measurement radar transistor and the receiver.In this paper, the front-end of radar is divided into millimeter-wave module,microwave PLL source module and IF module based on miniaturization and modularization. The millimeter-wave modules consist of millimeter-wave mixers and millimeter-wave VCOs. The microwave PLL source modules consist of C-band PLL circuits, millimeter-wave loop circuits and power supply circuits. The IF modules consist of IF amplifiers, mixers and base-band amplifiers. Large numbers of integration chips are used to achieve the miniaturization, higher stabilization and shorter researching time. The methods of mixing and digital dual-PLL are used for the miniaturization and higher working frequency of the frequency source. The method of Dick radiometer is used to reduce influence on radiometric sensitivity for gain fluctuation. The measured results of the microwave PLL sources show that output power is up to 10mW at 4.64GHz, 4.6GHz and 4.68GHz and the phase noise is up to -91.6dBc/Hz at offset frequency 10kHz. The results of the millimeter-wave sources show that output power is up to 10mW at 91.5GHz, 93.32GHz and 94.5GHz and the phase noise is up to -60dBc/Hz at 10kHz offset. The gain of the microwave IF module of the radiometer is 53dB from 40MHz to 2GHz and the gain fluctuation is less than 4dB. The IF module of the RCS measurement radar have 83dB gain on long-distance state and 54.5dB gain on short-range state, and the noise figure is less than 2dB. The measured result of the system in field shows that the performance of the radar front-ends meets the requirement of the users.