Ultrawideband Antennas for Multiband Satellite Communications at UHF-Ku Frequencies

In space-borne applications, reduction of size, weight, and power can be critical. Pursuant to this goal, we present an ultrawideband, tightly coupled dipole array ( TCDA) capable of supporting numerous satellite communication bands, simultaneously. Such antennas enable weight reduction by replacing multiple antennas. In addition, it provides spectral efficiency by reusing intermediate frequencies for inter-satellite communication. For ease of fabrication, the array is initially designed for operation across the UHF, L, S, and lower-C bands (0.6-3.6 GHz), with emphasis on dual-linear polarization, and wide-angle scanning. The array achieves a minimum 6: 1 bandwidth for VSWR less than 1.8, 2.4, and 3.1 for 0 degrees, 45 degrees, and 60 degrees scans, respectively. The presented design represents the first practical realization of dual polarizations using a TCDA topology. This is accomplished through a dual-offset, split unit cell with minimized inter-feed coupling. Array simulations are verified with measured results of an 8 x 8 prototype, exhibiting very low cross polarization and near-theoretical gain across the band. Further, we present a TCDA design operating across the upper-S, C, X, and Ku bands (3-18 GHz). The array achieves this 6: 1 bandwidth for VSWR < 2 at broadside, and VSWR < 2.6 at 45 degrees. A discussion on design and fabrication for low-cost arrays operating at these frequencies is included.