Dual-Polarized Tightly Coupled Array With Substrate Loading

A dual-polarized, tightly coupled dipole array (TCDA), delivering 13.1:1 bandwidth, is presented. The array incorporates a resistive sheet (R-Card) in the substrate to suppress resonances within the operational band and employs a dielectric layer as a superstrate to maintain high efficiency. The simulated infinite array demonstrates broadside VSWR < 2.5 across a 13.5:1 bandwidth, and VSWR < 3.1 for a 13.1:1 bandwidth while scanning up to 45 degrees with cross-polarization levels < -20 dB, in all planes. The array height, including the superstrate, is 0.08 wavelengths above the ground plane at the lowest operational frequency, and 1.1 wavelengths at the highest frequency. The infinite array overall efficiency, including mismatch reflections and aperture/resistive losses, is > 2.2 dB across all frequencies and scanning angles. An 8 x 8 prototype was fabricated and tested to validate the design. Measured array gain and mid-band and high-frequency patterns for the two principal scanning planes are presented, demonstrating good agreement with the respective simulations.