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Considerations in the simulation of large monolithic microwave integrated circuits enclosed in a conducting package

John Joseph Burke, University of Massachusetts Amherst


This thesis presents a numerical and experimental analysis of MMIC circuits enclosed in a conducting package. Three different simulation techniques are developed: a full-wave method of moments (MOM) procedure, a simple circuit model and the enhanced diakoptic method. In the design of MMICs, the effect of enclosing the circuit is typically assumed to be negligible. However, as the electrical size of enclosures increase package resonances are possible. If the system operates at frequencies near one of these resonances, coupling between the fundamental microstrip mode and the resonant mode is possible. This phenomenon is referred to as parasitic coupling to a resonant mode and its importance is emphasized in this thesis. An experimentally verified full-wave MOM procedure is used to examine some of the fundamental aspects of resonant mode coupling. In addition, methods of reducing this coupling will also be investigated. For example, both the addition of loss to an enclosure or layout modifications can be used to reduce resonant mode coupling. Since a full-wave analysis, although rigorous, is also very complex to implement, a simple circuit model is developed to describe resonant mode coupling. Simple analytical expressions for the entire model are easily evaluated, making this is a very attractive feature for implementation into a CAD package. In addition, it requires several orders of magnitude less CPU time than the MOM. As the size of MMIC circuits increase they become too complicated to analyze using a straightforward full-wave approach. A full-wave analysis of a typical MMIC of moderate complexity may require the solution of a large system of equations. Therefore, as second alternative to the MOM the diakoptic method is modified to analyze an MMIC in an enclosure. For very large circuits significant CPU savings result. A new spectral filtering technique, called the enhanced diakoptic method, is developed to improve accuracy.

Subject Area

Electrical engineering

Recommended Citation

Burke, John Joseph, "Considerations in the simulation of large monolithic microwave integrated circuits enclosed in a conducting package" (1993). Doctoral Dissertations Available from Proquest. AAI9316627.