Beam-Scanning Array Using Phase-Controlled Patch Antenna Exciting Even And Odd Modes For Millimeter-Wave Vehicular Communication

This paper proposes a millimeter-wave phase-controlled patch antenna by exciting even and odd modes. Furthermore, a phased array with large beam coverage for Vehicle-to-Everything (V2X) applications is implemented based on proposed phase-controlled antenna elements. The antenna is completed by connecting a circular microstrip loop with a square patch, and excited by two ports. Two shorting vias are loaded on the patch. Through the equivalent transmission-line circuit, even- and odd-mode resonance conditions of the antenna can be obtained. When phase difference between two ports is 0 or π, the antenna works in even or odd mode, respectively. In even mode, the antenna works in TM₂₂ mode, exhibiting a pattern with “∞”-shaped. In odd mode, the antenna has broadside pattern in TM10 mode. By mixing these two modes together, the proposed antenna achieves steerable radiation beam without any RF switch, varactor or tunable material. By using beam steerability of antenna elements, the designed phased array achieves a larger beam coverage of ±70° in a wider bandwidth of 24-30 GHz than other works. In addition, the array has lower profile and higher gain of 11.5 dBi with only 4 elements. Considering the advantageous performance, the proposed array is suitable for millimeter-wave vehicular communication.