An All-Metal, Simple-Structured Reflectarray Antenna With 2-D Beam-Steerable Capability

An all-metal reflectarray (RA) element based on the variable-rotation technique is presented in this letter. The RA element, based on an elliptical inner conductor and a circular outer conductor, exhibits continuous 360° phase coverage with negligible element loss over a wide range of incident angles and frequencies. A 10 GHz prototype with 121 manually rotated elements was simulated, fabricated, and tested. The proposed RA antenna has two-dimensional 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 26.2 dBi, corresponding to an aperture efficiency of 66%. A 1.3 dB gain drop was measured during beam scanning from 0° to 40°.