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

Abstract

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°. 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°± 2.9°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.

Phase inverter design using substrate‐integrated coaxial line with wideband performance

“…Recently, various forms of substrate‐integrated waveguides (SIWs) have been proposed owing to their numerous advantages, including lower loss, higher Q value, increased power‐handling capability, and effective metal shielding against environmental electromagnetic interference 8–10 . However, reported SIW‐based PIs are relatively scant 11–13 …”

“…[8][9][10] However, reported SIW-based PIs are relatively scant. [11][12][13] While the SIW PI offers various advantages, its operating frequency is limited by the non-zero fundamental-mode cutoff frequency, making it unsuitable for low-frequency applications. In contrast, the substrate-integrated coaxial line (SICL), 14 which resembles a conventional coaxial line, does not have a cutoff frequency for its fundamental mode and can be utilized at low frequencies.…”