Tightly-Packed Crossed-Dipole Array for L-band Satellite Communications

This paper describes the utilization of a tightly-packed crossed-dipole array antenna for L-band satellite communications. A thin-wire method-of-moments code called SPLAT (Scattering from Periodic Linear Arrays of Thin-wire Elements), which was originally developed for analyzing frequency selective surfaces, is used to perform a parametric study between the element spacing in the array and the impedance bandwidth. The results show that the mutual capacitance between the tightly-packed crossed-dipoles minimizes the variance in the array element current distributions across a one-decade frequency range of 0.3-3.0 GHz. This paper also demonstrates a wideband matching technique which takes advantage of this minimized variance in the current distribution. The wideband matching produces a better than 2: 1 impedance bandwidth, as defined by a voltage standing-wave-ratio (VSWR)below 2, at the antenna terminals. This tightly-packed crossed-dipole feed is designed as a non-scanning array for a deployable faceted reflector intended to be used onboard a geosynchronous L-band communications satellite.