Development of 60-GHz-band dielectric waveguide filter and investigation of flip-chip package structure

摘要

A planar dielectric waveguide filter with CPW I/O ports suitable for flip-chip bonding is proposed and is demonstrated for 60-GHz-band applications. The filter is formed incorporating metalized through holes in an alumina substrate. In order to improve stop-band rejection, short-circuited CPW resonators with a half wavelength are added to waveguide-to-CPW transitions. A fabricated 4-resonator filter exhibits an insertion loss of 3.2 dB with a 3 dB-bandwidth of 3.0 GHz at a center frequency of 59.5 GHz. The filter is mounted by using flip-chip bonding in a multi-layer ceramic package with a structure to suppress parasitically propagating electromagnetic waves. The flipped filter shows a stop-band rejection better than 35 dB from 50 GHz to 80 GHz.