High-Gain Phased Array Antenna With Endfire Radiation for 26 GHz Wide-Beam-Scanning Applications

In this communication, a high-gain phased array antenna with wide-angle beam-scanning capability is proposed for fifth-generation (5G) millimeter-wave applications. First, a novel, endfire, dual-port antenna element with dual functionalities of radiator and power splitter is designed. The element is composed of a substrate integrated cavity (SIC) and a dipole based on it. The resonant frequencies of the SIC and dipole can be independently tuned to broaden the impedance bandwidth. Based on this dual-port element, a four-element subarray can be easily constructed without resorting to a complicated feeding network. The endfire subarray features broad beamwidth of over 180°, high isolation, and low profile, rendering it suitable for wide-angle beam-scanning applications in the H-plane. In addition, the methods of steering the radiation pattern downward or upward in the E-plane are investigated. As a proof of concept, two phased array antennas each consisting of eight subarrays are designed and fabricated to achieve the broadside and wide-angle beam-scanning radiation. Thanks to the elimination of surface wave, the mutual coupling between the subarrays can be reduced for improving the scanning angle while suppressing the sidelobe level. The experimental predictions are validated by measurement results, showing that the beam of the antenna can be scanned up to 65° with a scanning loss only 3.7 dB and grating lobe less than -15 dB.