An ultra-thin, decade (10∶1) Bandwidth, modular “BAVA” array with low cross-polarization

Rockwell Collins has developed a novel design for a decade bandwidth, dual-polarized Balanced Antipodal Vivaldi Antenna (BAVA) array. The BAVA element height and the array lattice spacing are about λ/2 at the high frequency end of a grating-lobe free operating band. This allows an ultra-thin array profile, and will minimize the number (hence, cost) of transmit/receive (T/R) modules needed for high performance, multifunction phased arrays. The elements are fed directly by a 50Ω stripline. No matching network or balun circuitry is needed to achieve an active VSWR <; 3:1 across the entire bandwidth over wide scan volume. Although the design includes a ground plane, it provides a very low cross-polarization level due to its ultra-thin profile. The BAVA array produces below -25 dB cross-polarization at principal planes, and better than -17 dB at 45° scan-angles along the diagonal plane.