Broadband Rectangular Waveguide to Suspended Stripline Transition Using Dendritic Structure

A novel broadband rectangular waveguide to suspended stripline transition is presented at Ka-band. The transition is realized by using a $2^{\mathrm {nd}}$ order dendritic probe inserted into rectangular waveguide. To obtain a broad bandwidth, multiple resonances are excited for dendritic structure. To validate the proposed method, a back to back prototype transition is designed, fabricated and tested. The measured results show that the insertion loss of a single transition is <0.15 dB and return loss better than 20 dB over the full Ka-band (26.3-40 GHz). Moreover, the circuit is simple to implement. The measured percentage bandwidth for the transition is 41.32 %.