Millimeter-Wave Dual-Polarized Metal Transmitarray Antenna With Wide Gain Bandwidth

By utilizing the quadruple-ridged waveguide (QRW), a high-gain dual-polarized all-metallic transmitarray (TA) antenna with wide gain bandwidth is proposed. The QRW has a fixed height with four identical ridges symmetrically located inside a square waveguide. The phase compensation is obtained by simultaneously controlling the length of the four ridges. The fully symmetrical structure of the QRW enables the proposed TA to achieve dual-polarization and two-dimensional (2-D) beam scanning. The proposed TA antenna with an aperture of 112 × 112 mm is designed and fabricated by utilizing 3-D metallic printed technology. The measured broadside gain at 30 GHz for the two orthogonal polarizations is 28.2 dBi and 28.1 dBi, corresponding to an aperture efficiency of 41.9% and 40.9%, respectively. The measured 1 and 3 dB broadside gain bandwidth is 27.3% and 34.8%, respectively. The 2-D beam scanning range at 30 GHz for the dual polarized radiation covers ±18°, with a maximum scan loss of 2.3 and 3.2 dB, respectively.