High-gain end-fire radiation based on phase-reversal spoof surface plasmon polaritons.

A method to realize high-gain end-fire radiation based on phase-reversal spoof surface plasmon polaritons (SSPPs) is proposed in this paper. Phase-reversal SSPPs not only possess the ability to enhance the coupling efficiency between energy from the transmission line and air, similar to traditional phase-reversal structures, but also reduce the waveguide wavelength. This reduction increases the number of radiation units within the same size, providing significant advantages in terms of gain improvement of end-fire radiation. Specially designed branches where the phase is reversed for radiation capacity improvement and flaring ground at the feed port for mode conversion efficiency increasing are added to further enhance the gain of phase-reversal SSPPs-based end-fire radiation. Both the measured and simulated results exhibit good agreement, demonstrating that the maximum gain of the proposed phase-reversal SSPPs-based end-fire radiation reaches 17.1 dBi at a size of 5.9λ₀, with a relative bandwidth of 12.3%.