LTCC reduced-size bandpass filters based on capacitively loaded cavities for Q band application

The filter presented here is composed of cavities delimited in a LTCC substrate by a periodic lattice of metallized via-holes. The resort to LTCC technology permits us to improve the structure bulk by adding capacitive posts in the middle of the cavity. I/O CPW feeds are printed on the top face of the substrate and are suitable for planar circuit integration. A filter, functioning around 42.6 GHz with bandwidth at -3 dB of 7% and insertion losses lower than -0.6 dB has been designed and realized with success.