Empty substrate-integrated waveguide phase inverter in millimetre-wave band application

摘要

In this Letter, a novel empty substrate-integrated waveguide (ESIW) phase inverter (PI) applied in millimetre-wave has been proposed. ESIW PI, based on the structural symmetry design, is made of four parts: top cover, middle layer, ESIW PCB, and bottom layer. Owing to the reversed-phase transmission channel, the phase difference between the two outputs is absolutely equal to 180 degrees. The simulation and measurement results are in a good agreement. In the entire Ka band, the return losses, insertion losses and amplitude imbalance of ESIW PI are better than 12.7, 2.66, and 0.64 dB +/- 0.6 dB, respectively. Besides, the phase difference is within 180.5 degrees +/- 2.9 degrees in the same frequency band. In addition, the input and output ports are located in the identical circuit plane, which is easy to integrate with other devices and components.