Millimeter Wave Attenuation Characteristic Measurement Radar Front-end

Millimeter-wave technology has been widely used in various fields of defense, civilian, and scientific research. Although it has many advantages, its propagation characteristics are sensitive to environment. If there is rain, smoke or dust storm, the propagation attenuation will be serious, in most case to become one of its disadvantage. The wide application of millimeter-wave technology takes the study of its attenuation characteristics also ongoing.Based on the practical application of demand for the measurement of the smoke attenuation characteristic of millimeter-wave with the wavelength of8mm and3mm, in this thesis, two radar front-ends for attenuation measurement at wavelength of8mm (hereinafter referred to as the8mm system) and at wavelength of3mm(hereinafter referred to as the8mm system) have been proposed.The main contents are as follows:1. A detailed analysis and a reasonable design of the system have been made, according to the design requirements. Systems can work in far/short-range condition, in order to improve the dynamic range of the receivers.2. Phase-locking techniques and superheterodyne receiver structures are discussed. And the phase-locked sources in transmitters, the local oscillators and the IF modules in receivers are analyzed and designed.3. Debug each module in the two systems to achieve the design requirements. Then each module is assembled together for system debugging. The systems are required to work in the temperature from-10to50℃, so they must withstood the test of a high and low temperature testing. The problems in the debugging process have been analyzed and reasonable solutions also have been proposed.The output frequency of the transmitter of8mm system is35.28GHz with the phase noise-76.17dBc/Hz@10kHz. And its output power is-12.13dBm in the short-range condition and11.03dBm in the far-range, respectively. The gain of the receiver is35dB in the short-range condition,61.7dB in the far-range condition. The output frequency of the transmitter of3mm system is93.76GHz, with the phase noise -59.5dBc/Hz@10kHz, output power11.9dBm. The gain of the receiver is44dB in the short-range condition,70.1dB in the far-range condition. The two systems meet the design requirements.