Abstract
Increasing data transfer rates for future millimeter-wave communications requires high capacity radio channels and user-centric communication network environments. Therefore, special requirements, such as wide-angle beam steering, wide operational frequency bandwidth, and simultaneous operation with orthogonal polarizations, are essential for telecommunication antennas. In this communication, we present a compact patch antenna array with a Butler matrix (BM) feed network for the frequency band of 26-31.4 GHz. The 16-element planar array has been designed to operate with the two linear orthogonal polarizations and provide ±42° beam switching. To ensure the wideband operation, a novel combination of planar couplers, crossovers, and phase shifters is designed to form the BM. A new phase-shifter topology is used which is based on a combination of open-short stubs and the Shiffman phase shifter. The design is fabricated on a low-cost multilayer board with a size of 120 \times 70 \times 1.62 mm 3 . The size of the feeding network, which is implemented on a single board, is 76 \times 23 \times 0.1 mm 3 . The experimental measurements of return loss, mutual coupling, and radiation patterns confirm simulated results.