Flip-chip MMIC oscillator assembly with off-chip coplanar waveguide resonant inductor

摘要

A coplanar waveguide based microwave monolithic integrated circuit (MMIC) oscillator chip (14) having an active oscillator element (16) and a resonant capacitor (18) formed thereon is flip-chip mounted on a dielectric substrate (12). A resonant inductor (22) is formed on the substrate (12) and interconnected with the resonant capacitor (18) to form a high Q-factor resonant circuit for the oscillator (10). The resonant inductor (22) includes a shorted coplanar waveguide section (24) consisting of first and second ground strips (24b,24c), and a conductor strip (24a) extending between the first and second ground strips (24b,24c) in parallel relation thereto and being separated therefrom by first and second spaces (26a,26b) respectively. A shorting strip (24d) electrically interconnects adjacent ends of the conductor strip (24a) and first and second ground strips (24b,24c) respectively. A dielectric film (34) may be formed over at least adjacent portions of the conductor strip (24 a) and first and second ground strips (24b,24c). The resonant inductor (22) is adjusted to provide a predetermined resonant frequency for the oscillator (10) by using a laser (40) to remove part of the dielectric film (34) in the first and second spaces (26a,26b) for fine adjustment, and/or to remove part of the shorting strip (24d) at the ends of the first and second spaces (26a,26b) for coarse adjustment.