3D MMIC compact semi-lumped loaded CPW stubs for spurious suppression fabricated with a standard air bridge process

Compact and harmonic suppression semi-lumped stubs based on a CPW/thin film microstrip combination using 3D on-chip air-core solenoid and elevated symmetric inductors are proposed. The stubs are implemented using an MMIC airbridge process to realize an elevated transmission line and 3D inductors. These 3D inductors are used to load open circuit CPW/TFMS stubs in order to reduce their sizes. In addition to size reduction, an excellent suppression of spurious harmonic responses are achieved with improved dielectric loss which are inherent in these types of semi-lumped stubs. The experimental results presented in this paper demonstrate the validity of the design method.