The Phase Detection Technology Research For The Shortwave Antenna System

When humans enjoy the convenience brought by modern wireless communication technique, they also make greater demands on it. Especially for military wireless communication equipment, the electronic countermeasures capability is desired. The spatial power combining technique can increase the power of antenna system, which is an important means to improve the electronic countermeasures capability. As a key technique involved in the spatial power combining, the accuracy of phase detection affects the efficiency of power synthesis. With the above application requirements, a series of research is conducted in this thesis.The phase has been exploited for a long time, and there are several popular methods to measure it, including the phase measuring based on hardware circuits or software with signal processing algorithms. For the latter, however, the high measurement accuracy in theory is hardly reached in practice. With the development of integrated circuit, the radio frequency integrated circuit(RFIC) appears and is widely used in radio frequency measurement soon. As an integrated phase detecting device with high accuracy, AD8302 integrates logarithmic amplifier, phase detector and low pass filter in it. Based on simple measuring circuits and low costs of design and use, the phase of signals with intermediate or high frequencies can be measured accurately by AD8302, which has a certain research value.This thesis designs a system consisting of an industrial computer, a signal acquisition board and a circuit based on phase detector with high accuracy. It can measure phase differences, and has other functions such as signal processing and standing wave measuring. This system is designed on the principle of virtual instrument and has customizable software functions, which is an excellent characteristic. The final application software in Windows system is able to sample, analyze and process radio-frequency(RF) signals from antenna, including FFT, waveform restoration, spectrum analysis, phase difference detection and results display, etc.Since the phase detection equipment is installed and works near antenna arrays which cause a complex electromagnetic environment, its electromagnetic compatibility(EMC) should be considered. We refer to a great number of literatures in advance, conduct some reasonable electromagnetic compatibility design of the equipment, and carry out relevant experiments under existing conditions. In this thesis these methods are also introduced in detail.