A Ka-Band Third-Order Cross-Coupled Substrate Integrated Waveguide Bandpass Filter Base on 3D Ltcc

This paper presents a novel third-order cross-coupled rectangular cavity filter by using standard low-temperature co-fired ceramic (LTCC) technology, in which the multilayer substrate integrated waveguide (SIW) is implemented. Particularly, the desired filter has a single finite frequency attenuation pole at j4.0 with asymmetrical frequency selectivity. An experimental band pass filter (BPF) has been fabricated and measured. The insertion loss of the filter is better than 4.2 dB, and the 1 dB bandwidth is about 1 GHz at the center frequency 35.8 GHz. Good agreement is obtained between the simulated and measured S-parameters of the proposed filter. This filter can be used in millimeter wave secondary surveillance radars.