Estimating the Bandwidth of Spiral Antenna Arrays

An analytical method to estimate the bandwidth of planar phased array of spiral antennas is presented. Three main parameters are considered: circular polarization, reflection coefficient, and sidelobe levels. An application of the method for a planar array of asymmetrical Archimedean spirals is presented for a scan angle of
$\theta {= 30^ \circ} $
. The estimated bandwidth and the bandwidth obtained with the simulation results differ in 3.5%.