Analysis of a printed dipole active reflector

Active reflectors form a class of phased arrays that may be useful in systems such as space-fed radar antennas or wireless local area network repeaters. A wave incident on the reflector surface is received by an antenna array, amplified and phase shifted, and then re-transmitted. In the active reflectors considered in this paper, the re-transmission takes place from a second antenna array oriented orthogonal to the first. The cross-polarized nature of the incident and transmitted waves provides a means of improving the isolation between the two arrays. Where beam-steering takes place in either of the principal planes of the reflector, symmetry allows little coupling of energy between orthogonal antenna elements. If beam-steering is required in directions other than within the principal planes, however, substantial coupling may be expected. An active reflector constructed from orthogonal arrays of printed dipoles is analysed. The configuration of dipoles is chosen to retain the maximum possible substrate area for amplifier and phase shifter components, with a view to eventual monolithic integrated circuit fabrication.<>