Millimeter-wave wideband high-gain LTCC phased array antenna based on ridged substrate integrated waveguide

Abstract In this paper, a millimeter-wave (mmWave) wideband high-gain low-temperature co-fired ceramic (LTCC) phased array using ridged substrate integrated waveguide (RSIW) element is proposed, which can cover n257/n258 bands (24.25–29.5 GHz). First, a novel widebeam and high-gain RSIW slot antenna subarray is designed, which is constructed by staggered longitudinal slot that incorporated with additional radiating elements on the non-scanning plane. Further, the proposed widebeam antenna subarray is applied to construct a 1 × 4 array integrated in an LTCC package with small element spacing of about 0.41λ 0 . Moreover, by adding isolation slots and metal vias between adjacent array elements, the isolation of ports thereby is reduced below −15 dB, and the scanning range is increased up to ±7°. A wideband and low-loss feeding network is realized by series-parallel combined feeding, further improving isolation and scanning performance after assembly. The simulation and measurement demonstrate that the antenna array possesses satisfied beam-scanning capabilities over wide bandwidth of ∼20%, achieving maximum scanning angle up to ±62° while maintaining desirable gain above 14.5 dBi. Furthermore, within the entire operating bandwidth, the scanning angles extend to ±55° with minimal variation. These features show that the proposed antenna array is promising for 5G mmWave communications.