Wide‐Angle Scanning Ultra‐Wideband Phased Array Using Minaturised Antipodal Vivaldi Elements

ABSTRACT This paper proposes a novel phased array which has outstanding advantage of broadband, miniaturisation and wide‐angle scanning. First, leveraging a conventional antipodal Vivaldi structure enhanced with microstrip line side‐feeding, resistive loading techniques and top‐loaded radiating patches. Then, wide‐angle impedance matching and stable scanning performance are realised by incorporating a dielectric matching layer above the radiating element and introducing dummy elements at the array edges. Additionally, elliptical parasitic patches are integrated to suppress gain fluctuations during beam scanning. Finally, a miniaturised 6 × 10 finite array is fabricated and measured. Both simulated and measured results indicate that the array maintains an active voltage standing wave ratio (VSWR) below 2.5 across a 4:1 bandwidth (2.1–8.4 GHz), supporting scan coverage up to ± 60° in the E‐plane and ± 50° in the H‐plane. The gain fluctuations at key frequencies is constrained within 3 dB throughout the scan range. Therefore, the design achieves a comprehensive property of low cost, compact size, ultra‐wideband operation, wide‐angle impedance matching and wide‐angle scanning. This design demonstrates great potential for space‐constrained applications, particularly in airborne multifunction radar systems.