Optimization of a Multi-port Amplifier Using a Least Squares Evolutionary Relaxation Method
A satellite designed for mobile telecommunications applications may contain a large aperture reflector fed by an array at its principle focus. Each radiator element of the array has a one-to-one correspondence with a spot on the earth, so that radiation patterns are pointed at different locations on the Earth by different combinations of elements. Before the signals arrive at the array with their specified complex weights they must undergo amplification. This can be provided by a beam forming network composed of between 10 and 20 multiport amplifiers (MPA). The object of this paper is to describe an optimization method that will improve the performance of the beam forming network
Novel spread spectrum approach to multi-port amplifier calibration
This paper will outline the general design principles of multi-port amplifiers, along with operational and architectural benefits that they can provide. The paper will introduce the need for Multi-port amplifier calibration and present a Spread Spectrum based approach for unbalance detection and calibration which has been proposed by Eutelsat Communications, [RD1]. This Spread Spectrum approach has the advantage of requiring little to none on-board extra hardware and can be performed in real time without implications to communication traffic thanks to the peculiar properties of Spread Spectrum communication signals.
The evolutionary optimisation of shaped and minimum sidelobe radiation patterns for synthetic aperture radars
This paper presents a technique of optimising the aperture excitations of a N-element linear array of radiating elements for a spaceborne synthetic aperture radar (SAR), given a required far-field beam shape template. This method uses evolutionary or genetic algorithms to search and locate the best solution to the problem. It outlines how this technique may be applied to different types of space based SAR arrays and the various complications that are encompassed within the optimisation problem due to the real space scenario.