Design of wideband slot‐coupled microstrip vertical transition

A wideband slot-coupled microstrip-to-microstrip vertical transition is presented in this paper. The transition consists of upper/lower microstrip patch, a metallized via, a wide slot, and a CPW patch on the ground plane. The CPW patch is connected to the upper microstrip patch through the metallized via. The upper microstrip patch, the CPW patch, and the metallized via together constitute a hybrid resonator. By introducing the fundamental resonance of the hybrid resonator into the passband, a broadband microstrip vertical transition can be realized. A sample transition has been designed and measured. Experimental results indicate that a broad frequency range of 2.3 to 8.4 GHz with return loss better than 10 dB can be obtained.