Characterization and modelling of extremely high frequency enclosures

The development of monolithic microwave integrated circuits has prompted the need to develop specific types of enclosures for these circuits. The choice of enclosure depends on the intended frequency of operation since the performance of enclosures is affected by parasitic effects related to their construction and physical characteristics. These effects are caused by transitions, the cavity volume, the effect of the cover, and the electromagnetic coupling between the metallic walls and the encapsulated circuit. Two types of transitions are studied in detail through tests on enclosures made by Technical Components Inc. and by the French company SOREP. Results of time domain measurements are presented showing effects of electromagnetic coupling, covers, and cavity resonance. Many of the effects depend on the enclosure dimensions and all the effects studied contribute to a degradation in performance. The transitions between interior and exterior are the greatest causes of this degradation and their equivalent circuit models have the topology of a low pass filter.