High Isolation X-band and S-band Diplexers in Economical Technologies for Space Applications

This paper presents the development and test results of the X-band Substrate Integrated Waveguide SIW diplexer and S-band suspended strip line diplexer. It includes a description of the design flow and test plan issued for both diplexers, which are soon to acquire high Technology Readiness Levels (TRL). Complex topologies together with novel, economically attractive technologies, allowed for very compact final solutions. RF & thermal co-simulation and mechanical simulations for modal analysis, vibrations and shock have been performed prior to testing. Isolation level of more than 80 dB was achieved in both solutions, which is unique in planar filtering solutions. Final devices have been qualified and the S-band diplexer has reached TRL9, while the X-band diplexer has reached TRL7.