Design and Non-Intrusive Diagnostic of High-Gain Wideband Millimeter-Wave Active Antenna Array With Beam-Steering Capability for 5G Application

This paper presents a compact, broadband, beam-steerable antenna array designed for 5G millimeter-wave (mmWave) applications and the use of an electro optical field probe for its performance evaluation. The proposed array consists of 64 elements, arranged as eight-antenna sub-arrays capable of creating a narrow beam and achieving beam steering in horizontal direction. The 1×8 antenna array elements are configured in the vertical direction, and each is controlled by an 8-channel beamformer integrated circuit mounted on the backside, facilitating precise beam steering capabilities. The routing of DC and digital lines have been positioned on the surface of the array to achieve compactness. To improve impedance matching and suppress the grating lobe while steering, two parasitic 1×8 sub-arrays are incorporated into the overall compact design. The antenna array was designed, fabricated and experimentally validated. The proposed structure operates within the frequency range of 24.25 GHz to 29.5 GHz, covering the n257, n258, and n261 bands. Across these bands, the array exhibits a total combined active and passive peak gain of 33.89 dBi. Beam-steering measurement demonstrates that the antenna array can achieve a wide range of beam steering angles of ±45°.