Background Near-field beam focusing and steering of high-power microwave array antennas are required in applications such as high-power electromagnetic effect testing. However, existing phase-shifting surfaces, especially PCB-based designs, are limited in power-handling capability and are susceptible to inter-element coupling, which degrades the performance of near-field focused beams.
Purpose This paper aims to achieve near-field beam steering for high-power array antennas while maintaining high power-handling capability and preserving the phase integrity of the focused wavefront.
Methods A dual phase-shifting surface based on an all-metal sleeve structure is proposed. The system employs a 4×4 linearly polarized aperture-waveguide array as the feed source, above which two phase-shifting surfaces are arranged in parallel. The feed array is phase-compensated to generate a near-field focused beam on the axis at a distance of 0.5 m. Beam steering is realized by translating the upper phase-shifting surface, eliminating the need for complex electronic phase-shifting networks.
Results Simulation results at 9.5 GHz show that, under the constraint that the attenuation of the focused electric field at the target point is less than 1 dB, the proposed dual phase-shifting surfaces achieves beam steering within ±20° in elevation and full 360° in azimuth. Furthermore, analysis based on the simulated electric field distribution indicates that the power-handling capacity of the phase-shifting surface can reach the gigawatt (GW) level in a vacuum environment.
Conclusions The proposed all-metal dual phase-shifting surfaces provides an effective solution for high-power near-field beam scanning, offering high power capacity, simple mechanical control, and stable focusing performance.
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