A high-selectivity channel bandpass filter of satellite communication Ku-band input multiplexer

A design has been proposed of a $12$-pole waveguide bandpass filter with additional two inductive and two capacitive cross-couplings formed by corresponding small irises in metal walls between non-adjacent resonators. The central frequency of the filter passband is $f_0=12.73$ GHz, and its fractional bandwidth at the level of $1$ dB is only $\Delta f/f_0 = 0.3$% with the resonators' unloaded quality factor $Q_0=6\cdot 10^3$. In a traditional Chebyshev filter the unloaded quality factor of the resonator should be five times higher to obtain such characteristics. High selectivity of the device, as well as low ripple of the transmission coefficient and group delay time in the passband, is achieved by increasing reflection losses during filter synthesis. The design of the filter is intended for creating satellite communication multiplexers on its basis.