Compact filtering power divider based on corrugated third‐mode circular SIW cavities

Abstract

AbstractIn this article, a compact single‐layer filtering power divider based on third‐mode circular substrate integrated waveguide (SIW) cavities is proposed. The third‐mode SIW technique is introduced to divide an SIW cavity into three cavities and get 66% size reduction. The proposed power divider is composed of three third‐mode circular SIW cavities within a circuit with the size of a circular SIW cavity. The power is coupled from the input cavity to two output cavities through the electric coupling, separately. To achieve a more size reduction, the designed cavities are corrugated along the cutting planes. By increasing the length of the corrugated edges, the center frequency can be easily shifted to lower frequencies. In order to prove the proposed design procedure, the presented power divider with a second‐order bandpass filtering response is designed and fabricated. Reasonable agreements between the measured and simulated results are found. The measured results show that the power divider achieves an insertion loss of 1.2 dB at 5.61 GHz, return loss of higher than 14 dB, and 3‐dB fractional bandwidth of 7.8%. The results show that this power divider has the advantages of the compact size, high selectivity, and single‐layer structure.