An all-metal reflectarray (RA) element based on the variable-rotation technique (VRT) is presented in this letter. The RA element, based on an elliptical inner conductor and a circular outer conductor, exhibits a continuous 360° phase coverage with negligible element loss over a wide range of incident angles and frequencies. A 10GHz prototype with 121 manually rotated elements was simulated, fabricated and tested. The proposed RA antenna has 2-D beam-steerable capability up to 45° elevation angle. The measured results agree well with the simulated counterparts. For demonstration, four different steering cases are presented as examples by manually adjusting the rotation angle of the RA elements. The maximum measured antenna gain is 26.2dBi, corresponding to an aperture efficiency of 66%. A 1.3 dB gain drop was measured during beam scanning from 0° to 40°.

A novel all-metal circularly polarized radial-line slot array antenna (CP-RLSA) is presented in this paper. The RLSA is based on new CP unit radiators and is designed to be a standing wave antenna. A high circular polarization quality was achieved by utilizing these new CP unit radiators. A 14.25 GHz antenna prototype was simulated, fabricated and tested. Experimental results report a peak gain of 32.4 dBi. The antenna has excellent cross-polar rejection, with a measured cross-polar level of −30 dB in the main lobe direction. A beam-steering solution using the proposed RLSA is also presented in this paper, which is implemented through a pair of Pancharatnam–Berry metasurfaces (PBMs). These two PBMs are placed above the RLSA in the near-field region. For demonstration, four different steering cases are presented as examples. The measured results agree well with the simulated counterparts. The measured results of the antenna system demonstrate that the system can steer the beam to a maximum elevation angle of 45.8° with a maximum gain of 38.01dBi, corresponding to an aperture efficiency of 78.8%.

This work seeks a novel design for a compact leaky-wave array antenna for high-power microwave (HPM) applications. The leaky-wave waveguide antenna is made of rectangular waveguide with groups of non-resonant closely-spaced slots in the waveguide’s broad-wall. By this means, more slots can be set in a unit length with lower radiation power through each slot, then higher power-handling capacity and a compact longitudinal dimension and height can be achieved. An L-band leaky-wave waveguide antenna centered at 1.57 GHz has been designed and experimentally studied. The results show that the radiation efficiency of the antenna is more than 97% and the power-handling capacity of a single waveguide exceeds 1.3 GW. In addition, a 5-waveguide array antenna was also designed. The array antenna has an aperture efficiency of 76.6% and the beam scanning range can reach ±40° in H-plane, which would be suitable for many HPM applications.