A Ku-band satellite communication input multiplexer based on twelfth order waveguide bandpass filters

A four-channel Ku-band multiplexer for a satellite communication system has been developed, based on domestically produced components. The central frequencies of the channel passbands are 12.70, 12.74, 12.78 and 12.83 GHz, and their fractional bandwidths are $\sim$0.29%, measured at a level of 1 dB from the minimum loss level. High frequency selectivity of the channels in the multiplexer is achieved by using twelfth-order waveguide bandpass filters, in which two attenuation poles are formed to the right and left of the passband to increase selectivity. A miniature input filter of the multiplexer with a passband of 11.80–13.7 GHz, manufactured on coaxial resonators, provides an extended (over 35 GHz) high-frequency stopband with a suppression level of at least 60 dB. The results of mechanical and climatic tests of the created multiplexer confirm its compliance with the requirements for onboard satellite communication devices.