A beam-steerable lens antenna based on the concept of Risley prism is presented in this communication. The antenna is made up of a feed antenna and three transmit-array (T-A) lenses, including a stationary lens and two rotatable lenses. Beam steering is achieved by rotating the two rotatable lenses around the antenna axis independently. An antenna prototype has been successfully designed, simulated, fabricated and measured in Ku-band. The results show that the beam of the antenna can be steered to any direction within a 91.2° conical region. During beam steering, the measured peak gain of the antenna reaches 38.1 dBi, the maximum aperture efficiency achieves 80.5% and the gain variation is less than 1.7 dB. Moreover, the simulated results show that the power handling capacity of this antenna could reach GW level, which indicates application potentials of this antenna in high power microwave (HPM) field.

A beam-steerable wideband reflectarray antenna (WRA) is presented in this communication. The WRA element operated at 3.3-5.5 GHz (relative bandwidth 50%) exhibits a continuous 360° phase coverage and its power handling capacity (PHC) is estimated to exceed 4.5 GW/m ² in simulation, indicating its potential in high-power microwave (HPM) applications. Moreover, to verify the wideband performance of the WRA, a prototype was successfully designed, simulated, fabricated, and measured in S and C bands. The WRA prototype is composed of an ultra-wideband helical feed antenna, 25×25 antenna elements, and a dielectric plate as a radome. The results show that in the frequency band of 3.3-5.5 GHz, the WRA can achieve arbitrary direction of reflection beam within ±60° (120° conical region). Additionally, at the center frequency of 4.4 GHz, its sidelobe level is consistently below -15 dB, while the maximum gain loss is 3.3 dB during beam steering, and the maximum aperture efficiency reaches 67.89% in the direction of θ ₀ =0° and φ ₀ =0°.

In order to improve the performance of the existing high-power microwave (HPM) antenna, an all-metal circularly polarized (CP) reflectarray (RA) antenna is proposed in this article. The proposed antenna has 2-D beam-steerable capability up to 60 $^{\circ}$ elevation angle. The RA element employs an H-shaped slot and can be mechanically rotated to obtain continuous 360 $^{\circ}$ phase coverage with negligible element loss. By rotating the individual element, the RA antenna can achieve the dynamical control of the antenna beam. The maximum antenna gain is 33.05 dBi, corresponding to an aperture efficiency of 58.76%. In addition, the simulation results show that the power handling capacity of the RA antenna is over 5 GW/m $^{2}$ under vacuum condition, which can be applied to the HPM applications.

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°.

This work seeks a novel design for a compact leaky-wave array antenna for high-power microwave (HPM) applications. The leaky-wave antenna is made of a rectangular waveguide with closely spaced non-resonant slots in the broad-wall of the waveguide. By this means, more slots can be set within a unit length and less energy will radiate from each slot, then higher power-handling capacity can be achieved. An L-band leaky-wave waveguide antenna centered at 1.57 GHz is designed and experimentally studied. The results show that the radiation efficiency of the antenna is 97% and the power-handling capacity of a single waveguide exceeds 1.3 GW. In addition, a 5-waveguide array antenna is also designed. The antenna array 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.