Millimeter-Wave Wideband and Wide-Angle Scanning Phased Array Antenna Using Simple Scanning Enhancement Method

This letter presents a millimeter-wave(mmWave) wide-band and wide-angle scanning phased array antenna using a simple scanning enhancement method for small-scale array. Firstly, introducing a stepped ground (SG) can significantly broaden 3-dB beamwidth of the magnetoelectric (ME) dipole antenna element. Based on the wide-beam element, a 4×4 array is constructed with a spacing of only 0.378λ0(at 27GHz), and with SG, high frequency scanning gain improves by 6 dB, achieving a 61° max scan angle with no gain loss. To further enhance the scanning performance of the phased array, a metasurface structure (MS) is integrated, extending the scanning angle from 61° to over 66° and increasing the maximum scanning angle to 69°. Additionally, π-shaped and X-shaped decoupling paths are introduced to effectively reduce the coupling between adjacent elements as well as between non-adjacent elements. This approach enhances isolation, improves active S-parameter performance, and boosts efficiency. Fabricated using low-temperature co-fired ceramics (LTCC) technology, the antenna achieves a wide bandwidth of 24–29.5 GHz, covering 5G n257 and n258 bands, with a scanning range exceeding ±66°, and a gain fluctuation within 3 dB. Additionally, the coupling coefficient remains below -19.5 dB, while the active S-parameter stays below -10.3 dB at maximum scanning angles, and the efficiency surpassing 70%.