Very small wide-band MMIC magic T´s using microstrip lines on a thin dielectric film

An MMIC magic T (180° hybrid circuit) using microstrip lines on a thin silicon oxynitride (SiON) dielectric film is proposed. The microstrip-line area reduction is achieved by using thin-film microstrip lines, derived from the thin substrate structure, that have very narrow linewidths. The area is effectively minimized using meanderlike configurations. The SiON thin film is deposited by low-temperature plasma CVD (chemical vapor deposition). The MMIC magic T has been designed for a center frequency of 12 GHz, and small size with wideband performance from 6 GHz to 18 GHz has been achieved. Thus, magic T´s using thin-film microstrip lines are promising for miniaturized high-performance MMICs, such as balanced mixers and modulators