The W-band Low-noise Receiver Technology Research

Receiver front-end plays a critical role in microwave and millimeter wave radar system, and superheterodyne receiver is widely used in modern radar systems. The dissertation studies the theory and the design of the millimeter receiver front-end to meet the requirements of a project.According to the theory of superheterodyne receiver, a front-end is designed with double down-conversion based on hybrid integrated circuit. The simulation software ADS and HFSS are applied to assist design. Some components, including W-band rectangular waveguide filters, W band sub-harmonic mixers, microwave down-conversion modules and power source control module, are performed by theory studying, circuit designing and software simulation. Through deeply researching the topology of W-band sub-harmonic mixer, the shortage of traditional mixer structure is found, and a novel structure is proposed. The experiment result indicated that the minimum conversion loss of the mixer is 8.7dB, which is the best result in domestic W-band sub-harmonic mixer, and it is important in improving receiver noise figure. The three-order W-band rectangular waveguide filter which applied on receiver has a maximum insert loss of 1.2dB, a suppression of more than 30dB at an offset of -5GHz from center frequency, while the five-order W-band rectangular waveguide filter which applied on transmitter has a maximum insert loss of 1.7dB, a suppression of 63dB at an offset of -5GHz from center frequency. At the same time the four-order U-band rectangular waveguide filter has a maximum insert loss of 0.7dB, a suppression of more than 40dB at an offset of±5.76GHz from the center frequency. Microwave down-conversion modules convert down-conversion signal of millimeter wave to 60MHz and have a gain of 30±1dB with a noise figure of 2.1dB.Finally, it gives some improvement advice and easily ignored points, which can provide important roles for later research on it.