A 60 GHz-band planar dielectric waveguide filter for flip-chip modules

A planar dielectric waveguide filter with CPW I/O ports suitable for flip-chip bonding is proposed and demonstrated for 60 GHz-band applications. The filter is formed incorporating via holes in an alumina substrate. In order to improve a stop-band rejection, short-circuited CPW resonators with half wavelength are added to waveguide-to-CPW transitions. A fabricated 4-resonator filter exhibits an insertion loss of 2.8 dB with a 3 dB-bandwidth of 3.0 GHz and a rejection of 35 dB at a 3 GHz-lower-separation from a center frequency of 58.5 GHz. The filter is successfully mounted in a multi-layer ceramic package using flip-chip bonding.