Analysis of a partially sealed package for microstrip-line circuits

A partially sealed package formed by two metal diaphragms with or without an absorber is proposed and analyzed for shielded microstrip-line circuits. The mode-matching method, method of lines, and finite-element method are mixed appropriately to investigate the package. For a specific analysis, an electric current filament and a microstrip-line gap are chosen to simulate, respectively, an active circuit element (CE) and a passive CE to be packaged. The suppression effect of the package on the spurious (higher order) modes and the influence on the dominant mode are fully studied by comparing the excitation and scattering characteristics of the CE's with and without the package.