Provided is a method for adjusting Fast Fourier Transform window positioning in a Multi Band Orthogonal Frequency Division Multiplexing Ultra-Wideband system. Ideally the material includes a third layer adapted to collect energy and convert the energy to electrical energy for storage in the first section. The leg device includes a pivot unit for interconnecting at least three leg members such that the leg members are pivotable relative to the pivot unit to be angularly equidistant when the leg device is in the extended state, and to be moved toward each other when the leg device is in the folded state.