Compact and Narrow-Band Waveguide Filters Using TM Dual-Mode Cavities for Input Multiplexer in Communication Satellites

This paper presents a compact and narrow-band filter using TM dual-mode cavities, in Ku-band to be used as a channel filter in IMUX of a satellite transponder. The basic structure is the TM dual-mode cavity. To achieve a compact and high Q resonator, such a cavity exploits a pair of degenerate modes (TM₁₂₀, TM₂₁₀). In this achievement, a single cavity can provide two transmission zeroes besides two poles. The design of a four-cavity filter is reported and compared with the experimental results at 10.97 GHz center frequency with 36 MHz bandwidth. The obtained results satisfy the specification requirements. The agreement between HFSS simulation and the experimental results demonstrates the effectiveness of the proposed design approach.