A Symmetrically Excited Microwave Rotary Joint

A waveguide rotary joint for operation in the frequency range 28-31 GHz is described. The construction of the joint is simple, as the symmetrical excitation employed for mode conversion obviates the need for mode filters. The joint may be used without tuning at certain optimum frequencies such that insertion loss is always better than 1 dB. The joint may be tuned for operation at any required frequency within the band.