Design And Implementation Of Microwave Coaxial Cavity Bandpass Filter

As one of very important microwave components, coaxial cavity filter received extensive attention from many scholars and researchers. Because of its higher quality factor, small volume, low insertion loss, further parasitic passband and can bear larger power, easy processing characteristics, coaxial cavity filter has been widely used in the areas of modern communications.This topic is derived from a nuclear magnetic resonance spectrometer equipment company 500 M nuclear magnetic resonance spectrometer system project requirements to design a kind of microwave band pass filter which is suitable for the nuclear magnetic resonance spectrometer.The author through research and analysis and designed a microwave comb coaxial cavity bandpass filter for this eqipment.Using MATLAB programming software integrated coupling matrix of the filter approximate function, using circuit and electromagnetic simulation software collaborative simulation method to realize comb coaxial cavity microwave bandpass filter overall optimum electromagnetic design, simulation and realization of the filter overall design.This thesis first introduces some of the basic theory about microwave cavity filter design, such as: the approximate function of filter and their response characteristics, the design method of general design table low-pass prototype circuit structure, a prototype network transformation and its frequency response after transformed,, the low-pass prototype circuit of coupling resonance microwave bandpass filter,these are the basis to make sure complete the microwave cavity bandpass filter design smoothly.Next, this thesis introduces the theoretical basis and method for the coupling matrix filter step,establish chebyshev band-pass filter circuit model,design implementation of chebyshev bandpass filter coupling matrix model by a software solution,with the solving process of filter circuit parameters and frequency response curve fitting and drawing. On this basis,concept design process of the coaxial comb cavity band-pass filter,combining with the instance, design simulation implementation of a comb cavity bandpass filter for nuclear magnetic resonance spectrometer, and make quantitative calculation and forecast for the power capacity of cavity. Finally, with the help of structural engineers in the company,complete the physical production, complete physical debugging and testing.