Design of a Microwave/Millimeter-Wave Shared-Aperture Antenna by Hybridizing Series-Fed Antenna Array and Leaky Wave Antenna

Applications operating in both microwave (MW) and millimeter-wave (MMW) are important for future wireless communication systems. To fulfill the requirements of dual-band applications, a novel shared-aperture antenna is proposed with broadside radiation in both MW and MMW bands. Series-fed planar inverted-L antenna (PILA) elements are symmetrically placed to design an MW-band array with broadside radiation. A novel MMW-band leaky wave antenna is integrated into the PILA array as a transmission line in the MW band. Our analysis reveals that the proposed leaky wave antenna can suppress unwanted radiation from the MW array in the MMW band. Therefore, the MW array and the MMW leaky wave antenna can be integrated into a shared aperture for a compact design. The leaky wave antenna is designed with a nonuniform configuration to mitigate the open stopband (OSB). The fabricated prototype produces broadside radiation in the MW band from 3.46 to 3.72 GHz, with a peak gain of 7.6 dBi. Frequency-scanning beams are generated near broadside in the MMW band. Within the operating band from 30 to 40 GHz, the main beam scans from −21° to 14° with a realized gain varying between 12.5 and 15.7 dBi.