Phased Array With Low-Angle Scanning and 46:1 Bandwidth

An extremely wideband (EWB) antenna array is presented that covers the UHF to C-bands (0.13-6 GHz). The array has dual-linear polarization and is capable of wide-angle scanning. Notably, this array achieves a 46:1 contiguous impedance bandwidth at broadside with VSWR <; 3.1 across most of the band and VSWR <; 4 when scanning down to 60° in the E-plane across the band. In the H-plane, the VSWR worsens when scanning down to 60°. In addition to building on the tightly coupled dipole array concept, the enabling novelty of this EWB array is the use of a frequency-selective surface (FSS) resistive card (R-card) within the substrate that suppresses periodic ground plane interference. Also, a highly improved impedance matching network with tapered stripline balun is employed. A 12 × 12 array prototype was fabricated and tested to verify the bandwidth and gain performance of a finite array. The simulated radiation efficiency was demonstrated to be 72% on average across the band.