Research On Microwave Passive Network Miniaturization Technology

Microwave passive networks are indispensable constituent of systems such as communication, microwave satellite communication and electronic countermeasures in modern microwave. The most important microwave passive component with the most advanced technology is microwave filter. Its performance can directly influence the quality of the whole communication system. With the constant development of satellite, microwave filter technology is facing more and more challenges. It is a trend to improve properties of the circuit and reduce the size and weight of components microwave filter technology. The rapid development of personal communication system requires low-power and small passive filter device and the application of large-platform satellite with increasing available energy sources, which ushers in a new research direction that high-power filter with moderate size and weight can meet the requirement of power volume in the vacuum and high-power work environment. Many important unit resonators of the filter have many special features whose reasonable application can help produce various well-structured microwave nets. These sound properties will be used to improve circuit properties and optimize system design.In this dissertation, the miniaturized design of microwave filter and miniaturized application of resonators in various circuits are studied in an innovative and explorative way, including:1. The filter function pre-distortion technology that can meet the requirements of high selectivity and miniaturization is studied. By analyzing a set of numerical examples, pre-distortion filter function scope and requirements of the resonator for achieving the function are given. Conditions of SIW structure of realizing pre-distortion filter is studied according to the characteristics of the function. Due to its small value of Q and poor tenability, this structure is not fit for realizing the function. Therefore, a new resonator with high-value Q and multilayer PCB technique is proposed. The value of Q measured can reach 1000-2000, which is a new way of realizing pre-distortion filter with PCB technique.2. The working condition of vacuum high-power coaxial resonant cavity that is widely used in low frequency band of microwave is studied in-depth. A coaxial resonator with similar size, weight and structure of common coaxial resonator but 1-3dB higher multipactor threshold is proposed, providing new technology reserve for the miniaturized design of vacuum high-power coaxial filter.3. The characteristics of resonator-major constituent of filter are studied in-depth. And the moderate application of these characteristics reveals:out band rejection symmetric Ka frequency band can directly couple thick-film filter when its size reduces to 2/3. If the filter is regarded as the resonator with good properties, a method of designing the multi-channel filter whose input and output are connected through splitting waveguide. The filter designed by this mothod has independent center frequency and operation bandwidth is put forward, which facilitates the well-structured design and optimization of broadband system. The 180°hase-shift network of 44% broadband is used in C frequency band and the size of this network is as small as the one-yuan (RMB) coin.