Dual-band switched beam array fed by dual-band Butler matrix

A two layer dual-band switched beam system operating at two separate frequency bands is proposed. This system consists of a dual-band 4 × 4 Butler matrix at the bottom layer and a dual-band microstrip antenna array at the top layer. The antenna array is fed by a Butler matrix to produce four beams that can be tilted in different four directions. A modified Butler matrix consists of branch line couplers and -45° phase shifters without any crossovers. The system provides a tilted beam of ±14° and ±47° at 3.95 GHz and ±10° and ±28° at 7.3 GHz.