Compact 3D integrable SU8 embedded microwave bandpass filters using complementary split ring resonator loaded half mode substrate integrated waveguide

Abstract

A 3D integrable, compact SU8 epoxy embedded evanescent wave half mode substrate integrated waveguide (HMSIW) microwave resonator and a bandpass filter at 12GHz (Ku band) have been designed and fabricated by using a multilayer surface micromachining fabrication process. Evanescent wave amplification with forward transmission below the characteristic waveguide cutoff frequency is achieved with the use of complementary split ring resonators (CSRR) loaded on the top surface of a half mode substrate integrated waveguide, resulting in compact resonators with controllable Q factor and dual band operation capability. The use of the photopatternable SU8 epoxy as the dielectric for implementing the embedded RF passive devices enables tall vertical interconnects and multilayer 3D passives with high-Q factors, the integration of MEMS devices on CMOS circuits with its low temperature capability, and batch fabrication of multiple devices. Full wave electromagnetic simulations shows promising results at 12GHz, with a Q factor of 12 to 19 and a great size reduction of more than 50% when compared with conventional PCB implementations.