A Ka-band FSIW band-pass filter with LTCC technology

A Ka-band compact band-pass filter is presented in this paper based on folded substrate integrated waveguide (FSIW) resonators in multilayer low-temperature co-fired ceramic (LTCC). The FSIW resonator is formed by inserting a metal plate with two orthogonal slots into the cavity, which is used for the circuit size reduction with its footprint about a quarter of the conventional TE₁₀₁ mode and also has advantages of high Q and low-loss. The vertically stacked cavities are coupled by “Circle”-shaped slots. Then, a two-order cross-coupling FSIW cavity filter is proposed. The simulation results show that insertion loss and return loss better than 0.3 dB and 20dB, respectively, in the pass-band of 30.1-31.2GHz. Moreover, the filter has compact size and achieves two transmission zeros at both low and high rejection bands.