W-band Measurement Radiometer Receiver Design

In this paper, a W-band K-factor radiometer system is studied for millimeter-wave radiation-measuring of subaerial object in detail, and the system parameter of the radiometer receiver is analyzed and designed, and its Intermediate Frequency Amplifier Module and low-frequency circuit assembly are realized.In theoretical analysis of the system, four types of a radiometer ,a total power radiometer, a Dicke radiometer and its two changing types, are discussed and their work principle are analyzed. Compared with their advantages and disadvantages in terms of their performance and implementing difficulty in the existing condition at home, this dissertation establishes the system scheme. Taked into account the difficulty in both the design and purchase of Low-noise Amplifier (LNA), a K-factor radiometer system is adopted with a LNA or without a LNA. In the paper, major parameters of all components of the receiver are assigned and computed in detail. After simulating the whole designing system, it's found that results are consistent with the design value. At the same time, the harmonic performance is simulated to analyze its impacts on the Ultra-wideband IF Amplify Module, results show that the system has good harmonic suppression.In the system's concrete design, a multi-mode horn antenna is used for the millimeter wave radiometer, whose side-lobe is under -35dB at 94.5 GHz for result of simulation with HFFS software. And a design of RF front-end, such as the W-band Low-noise Amplifier and mixer assembly, is discussed. Then this dissertation simulates and designs the IF Amplifier Module, and simulates effect of the Ultra-wideband LC Filter on the parameters of the IF Amplifier Module. Through simulation, the Ultra-wideband IF Amplifier Module is optimized and debugged. And the practical debugging results is shown well of the IF Amplifier Module. At last, the design and debug of the square-law detector and the low-frequency circuit assembly are achieved.