An Adaptive Five‐Element Array Antenna Based on Miniaturised Polarisation‐Insensitive Absorptive Metamaterial for Anti‐Jamming Applications

ABSTRACT This paper proposes a polarisation‐insensitive absorptive metamaterial unit cell that achieves a perfect absorption of circularly polarised (CP) incident waves. To overcome the miniaturisation limitations inherent in conventional metamaterial designs, an innovative approach employing a sandwiched configuration with cladding layers is introduced. This approach approximates perfect electric conductor (PEC) boundary conditions, enabling the truncation of the bulky periodic structure into a one‐dimensional wall‐type absorptive metamaterial (WAM). To mitigate mutual coupling under stringent aperture constraints, four WAM screens are integrated concentrically around the central element of a compact five‐element array antenna featuring sub‐wavelength element spacing (0.4λ) at the GPS L1 frequency. Both simulations and experimental results demonstrate inter‐element mutual coupling suppression of less than −23 dB between the central and peripheral elements, alongside a peak realised gain improvement exceeding 3 dB for the central element. The WAM‐enhanced adaptive five‐element array achieves a maximum improvement of 4 dB in anti‐jamming capability.