Vertical Waveguide-to-Microstrip Self-Diplexing Transition for Dual-Band Applications

This letter presents a novel vertical waveguide-to-microstrip self-diplexing transition for dual-band applications. The transition is realized with standard printed circuit board (PCB) manufacturing processing, making it suitable for mass production and practical applications. A standard waveguide is screwed on the topside of the stack-up. Dual-band self-diplexing operation is achieved by coupling two microstrips (one for each band) to two radiating patches through H-shaped slots. The operating bandwidth has been enhanced by adding two parasitic patches above the radiating ones. Metalized via holes are used to form a cage around the rectangular waveguide and the microstrips to prevent power leakage. A prototype has been fabricated to operate at K/Ka frequency band. The experimental results show a $-$ 10 dB matching bandwidth of 20% and 14% for the lower and upper bands, respectively. Within these ranges, the maximum measured insertion loss is about 0.6 and 0.7 dB, respectively.