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
Synthesis of SAR radiation patterns incorporating mutual coupling by using genetic methods
This paper presents a technique for synthesising the element excitations of an N-element linear array of radiating elements, given a required far-field beam shape template. It also performs the synthesis in the presence of mutual coupling across the array. This method uses an evolutionary or genetic algorithm to search and locate the best solution to the problem. The method takes into account additional aperture constraints including amplitude range or uniform amplitude taper. It can also optimise for simultaneous synthesis of transmit and receive radiation patterns commensurate with standard SAR operation. It also presents some synthesised complementary Tx and Rx patterns and their corresponding measured results. >
Can Centauros or Chirons BE the First Observations of Evaporating Mini Black Holes
We argue that the signals expected from the evaporation of mini black holes — predicted in TeV-gravity models with large extra dimensions, and possibly produced in ultrahigh energy collisions in the atmosphere — are quite similar to the characteristics of the Centauro events, an old mystery of cosmic-ray physics.