Travelling-Wave SIW Transmission Line Using TE20 Mode for Millimeter-Wave Antenna Application

A novel periodic substrate integrated waveguide (SIW) leaky-wave structure using TE20 mode transmission line (TL) for millimeter-wave antenna applications is proposed and studied in this paper. The electric field distribution and dispersion properties for TE20 mode SIW-TL is first studied and presented. Based on the current distribution of the TE20 mode, elliptical slots are periodically embedded on the surface of the SIW-TL, which not only achieves backward to forward continuous beam-steered boresight radiation, but also maintains good TE20 mode transmission. Two half-wavelength slots are etched on the bottom of SIW, which successfully excite TE20 mode in TL. For experimental verification, a periodic TE20 mode SIW-TL leaky-wave antenna is fabricated. The measured and simulated results are in good agreement. The measured -10 dB bandwidth, peak gain, beam scanning range is 25.5–33.8 GHz (28.0%), 15.4 dBi and 50° to -18° (backward to forward), respectively. It demonstrates a simple structure and good travelling wave properties with wide bandwidth, high gain, and good radiation performance, which is suitable for 5G millimeter-wave application.