Dual-Band Fixed-Frequency Beam-Scanning Leaky-Wave Antenna for Large-Frequency-Ratio Microwave and Millimeter-Wave Applications

A dual-band fixed-frequency beam-scanning leaky-wave antenna (LWA) operating in C and Ka bands is presented in this article, exhibiting a large-frequency-ratio property. A microstrip line (MSL) is employed on the top layer to feed the patches operating in the low-frequency band, and an air-filled low-loss gap waveguide (GW) is introduced at the bottom of the antenna to feed the patches operating in the high-frequency band. By changing the biasing states of the soldered p-i-n diodes, the operation states of all the radiating patches for the low and high bands can be switched between on and off. Then, based on the holography theory, the hologram is generated on the radiating aperture of the LWA, which can be manipulated to produce expected radiation, and hence, the dual-band fixed-frequency beam-scanning property is realized. In addition, the presented antenna is fabricated and measured for validations. Good agreement can be found between the simulated and measured results, with a peak realized gain of 8.9 dBi at 4.85 GHz and 17.2 dBi at 27 GHz, showing a desirable dual-band operation ability with large frequency ratio. Scanning ranges of 100° are achieved in both bands, demonstrating that the developed antenna has great potentials to large-frequency-ratio microwave and millimeter-wave applications.