Time-domain Spectrum Analysis Of Microwave Mixer

Mixers are widely used in communications, radar and guidance. Its performance directly affects the quality of the entire receiver system. As a result, how to accurate simulation/accurately simulate mixer in early design is particularly important and people have been researching on the subject since then.In traditional methods to analyze the mixers, such as the harmonic balance method, the transform matrix method, the accuracy of the method depends on parameter extraction of lumped and distributed parameter circuit elements and the highest order of harmonic selected. As the frequency increases, the traditional methods can not take the electromagnetic effects of microwave circuits, as well as cross-coupling into account. This requires the usage of full-wave analysis to ensure the correctness of the electromagnetic response of the encapsulated circuitry and the system early in the mixer circuit design. To numerically model the mixer structure of three-dimensional electromagnetic field, development of fast and accurate electromagnetic methods have been the focus of researchers. To achieve this goal, based on the EM field numerical algorithm, this thesis contains the study of the extended spectral-element time domain method (SETD), and applies these technologies to the microwave and millimeter wave circuits, especially active nonlinear circuits electromagnetic analysis.The SETD method is a new method using curved hexahedral elements. But the traditional SETD method can not be directly applied to the analysis of nonlinear circuits. Thus a new time domain electromagnetic field-circuit hybrid algorithm is proposed to analyze microwave mixers based on SETD. This simulator allows the diode to be characterized by a nonlinear equivalent circuit, while taking into account the EM coupling between the diode and the distributed circuit. Using this method, the mixer simulation can be successfully achieved. The noise effects and high-power microwave effects are analyzed finally.