Hybrid-Decoupling-Based Shared-Aperture Phased  Array Antenna for Ku/Ka-Band with Low Profile,  Wide-Angle Scanning and High Isolation

This paper presents a low-profile Ku/Ka dual-band shared-aperture phased array antenna (SAPAA) that addresses conventional limitations in profile height, port isolation, and scanning angles through a hybrid-decoupling approach combining array decoupling surfaces (ADS) with defected ground structure (DGS), complemented by structural reuse techniques. The Ka-band elements utilize co-designed array decoupling surface layers integrated with DGS to effectively suppress surface current coupling, achieving wide-angle scanning capability of ±45◦ across the 32–36 GHz frequency band. For the dual-polarized Ku-band elements, feed matching is optimized through cross-shaped slots employing DGS structural reuse, demonstrating orthogonal port isolation exceeding 35 dB within the 14–18 GHz operational band while extending the scanning range to ±55◦ in both E- and H-planes. The antenna features an ultra-thin profile of merely 2.35 mm (0.28λh), with measured inter-band isolation reaching 35 dB in the Ku-band and 18 dB in the Ka-band. Experimental verification confirms the design’s high performance and practical utility, offering a compact solution for multi-band integrated communication systems.