LAUSR

In this article, a method for designing multichannel bandpass filters (BPFs) based on trimode dielectric-loaded cavities is presented. A large number of BPFs are integrated as one multichannel BPF with multiple inputs and multiple outputs, resulting in an ultracompact size. The cubic trimode dielectric-loaded cavities are utilized with the TE101, TE011, and TM110 modes resonating at the same frequency and orthogonal to each other. Feeding probes and coupling probes are properly arranged where the three modes in one cavity can be excited for different BPF channels without interference with each other. Consequently, excellent isolation among multiple channels can be obtained. The multichannel BPF is designed based on a 3-D structure, which can be easily extended to higher filter orders with a larger number of channels to satisfy different requirements in wireless systems. For demonstration, a 12-channel BPF is fabricated and measured, which exhibits good filtering responses of each channel and high isolation among channels. Significant size reduction is achieved compared to conventional multiple single-channel filters, which is potential in high-integration base station applications.