A Tightly Coupled Ultra‐Wideband Antenna Array With Wide‐Angle Scanning Capability Based on a Novel Interdigital Structure

To address the urgent demands of modern electronic countermeasure systems for antennas with ultra‐wideband performance, high gain, and wide‐angle scanning capability, this paper proposes a novel dual‐polarized wideband antenna structure. The antenna is based on a dipole‐patch element, in which a newly designed folded interdigital structure is introduced to enhance coupling and achieve ultra‐wideband operation. Furthermore, a resistive frequency selective surface (RFSS) is incorporated to eliminate radiation nulls across a broad frequency range. A cross‐shaped wide‐angle impedance matching (WAIM) layer is also designed to improve impedance matching on the array aperture, enabling wide‐angle scanning. Based on full‐wave simulations, a 10 × 10 array prototype is fabricated and measured with an overall profile height of 10 mm. Measurement results indicate that within the 1.6–19.7 GHz range, 80% of the in‐band S 11 values remain below −7.5 dB, while the array achieves a gain higher than 10 dBi within the 4–18 GHz band and supports ±45° scanning. These results validate the feasibility and effectiveness of the proposed antenna structure for ultra‐wideband and wide‐angle scanning applications.