A Wideband Substrate Integrated Waveguide Bandpass Filter for 5G Millimeter Wave Transceiver

A substrate integrated waveguide (SIW) bandpass filter (BPF) for 5G millimeter wave (mmW) applications is proposed. First, a wideband grounded coplanar waveguide (GCPW)-to-SIW transition is designed for 22 GHz to 35 GHz. An SIW filter with eleven cavities arranged in a zigzag manner is designed to achieve the desired passband characteristics in the 5G mmWave band at 28 GHz and to reject harmonics caused during frequency up-conversion from baseband. The overall filter performance has been maximized by adjusting the dimensions of individual cavities, introducing openings at decoupling walls between cavities and chamfering cavity corners. Full-wave EM simulation with CST Microwave Studio is used for this optimization. The measured low side rejection and the insertion loss are comparable with the simulated results.