Development of Substrate Integrated Waveguide filters for low-cost high-density RF and microwave circuit integration: Pseudo-elliptic dual mode cavity band-pass filters

Abstract

The properties of dual mode resonance in planar SIW-based rectangular cavities are investigated and discussed. A specific mode combination of dual mode cavity presents a unique frequency response feature. With the aid of an optimization process or software, it is convenient to cascade a number of cavities with coupling apertures to form a filter. A 3-cavity pseudo-elliptic SIW filter based on H203 &H104 hybrid resonance is designed and fabricated on a Rogers TMM3 substrate. Measured results show that the insertion loss at the central frequency around 24GHz is 4.58dB and the return loss is better than 20dB in the whole pass-band of 760MHz. The design method can widely be used for high-density microwave integrated circuits and the mass-fabrication of such filters is made easy even when keeping development and processing costs very low.