All Metal Focusing Transmitarray Antenna for High-Temperature Plasma Diagnosis

In this paper, an all metal focusing transmitarray antenna using a II-shaped slot element is proposed. The transmitarray is formed by stacking four identical metal phase shift layers and three identical square waveguide layers on each other. To meet the requirements of high-temperature plasma transmission diagnosis, a 2024 aluminum alloy material is used. The simulated results indicate that, unlike the feed antenna, the proposed antenna can concentrate most of the electric field energy into a small area. To verify the design, a fabricated prototype was processed and measured in the C-band. The results show that the proposed antenna achieves an average focal spot diameter of
$1.3~\lambda _{0}$
at 5.7 GHz and it can work in the 5.4-6.0 GHz band. Furthermore, all metal focusing transmitarray antennas have great potential for high-temperature plasma diagnosis.