A Compact K-/Ka-Band Waveguide Transition with Integrated Diplexer and Power Divider

The component presented in this work combines three functionalities, i.e., a waveguide transition, frequency separation, and power division. A rectangular waveguide (RWG) serves as common 20/30 GHz port. The signals are diplexed into two 20 GHz and four 30 GHz grounded coplanar waveguides (GCPWs). The required 3 dB and 6 dB power division ratios are achieved reactively and by exploiting symmetries. Both passbands feature a -10 dB reflection bandwidth of more than 1.2 GHz, an insertion loss below 1.3 dB, an isolation exceeding 25 dB, and an amplitude imbalance of less than 1 dB. The component occupies only 9 x 9 mm² on a single layer printed circuit board (PCB) and is thus suitable for application in highly integrated phased array front-ends.