New and improved method of beam forming with reduced Side Lobe Levels for microwave power transmission

Solar power satellite (SPS) is one option for meeting the huge future energy demand as the Earth will require sustainable electricity sources equivalent to 3 to 5 times the commercial power presently produced by 2050. One of the critical goals of SPS is to maintain highest beam efficiency (BE) because the microwaves (MW) from SPS will be converted to utility power unlike the MW from communication satellites. Therefore the SPS will need a highly efficient microwave power transmission (MPT) system. Another aspect of SPS is to maintain side lobe levels (SLL) as minimum as possible to reduce interference to other communication systems. The SPS costs can be reduced if MPT efficiency is increased. Edge tapering of a phased array antenna, that requires a complicated system, is one way to decrease SLL and increase BE. It is also possible to achieve minimum SLL with randomly spaced element position but it does not guarantee higher BE and the determination of random element position is also a difficult task. A new method of edge tapering system from the concepts of isosceles trapezoidal distribution (ITD) of array excitation and unequal element position of antenna array was investigated both through the simulation and the experimentation. The method is named as dasiaITD edge tapering with unequal element spacing (ITDU)psila. ITDU method was compared with Gaussian edge tapering and simple ITD edge tapering. The lowest maximum side lobe level (MSLL) and the highest BE was achieved in newly derived ITDU technique.