Active Antennas for Commercial and Military Communications Satellites – A Review

Active antennas have been in use in communications satellites for decades. The antenna configurations include array-fed reflectors, multiple-beam lenses and direct radiating phased arrays. The active feedings of the antennas include single amplifier per radiating element and matrix power amplifiers shared between clusters of radiating elements. This paper reviews the combinations of antenna configurations and active feedings as applied to different satellite systems. The miniaturization of active and beam forming components using MMIC technology are also addressed. The examples presented in this paper scan four decades of development at all frequency bands from Lto Ka-bands. The applications cover commercial and military systems with multiple spot beams, cellular mobile systems, broadband systems and dynamic high-power high-capacity systems.