Dual-band slot microstrip patch antennas with dual-radiation modes for wireless communication

In this paper, a novel compact dual-band microstrip patch antenna with dual-radiation modes is investigated. The proposed antenna consists of a rectangular ground plane, a U-shaped feed probe, and an H-shaped slot radiating patch. By adjusting the size of these structures, a dual-band antenna can be obtained. In the low-frequency band, the antenna can radiate one radiation beam with high gain. In the high-frequency band, the antenna can achieve monopole-like radiation pattern. Therefore, an antenna prototype is fabricated and measured for validation. Good agreement between the simulated and measured results is observed in this paper. The antenna's operating frequency ranges are 3.6-3.85 GHz in the low-frequency band and 5.1-6.1 GHz in the high-frequency band with the reflection coefficient less than -10 dB. At 3.7 GHz, the antenna radiate one beam with 8.8 dBi realized gain. At 5.5 GHz, it exhibits dual-radiation beams directed to -48 and 48° with 5.6 and 5.5 dBi realized gain in the xoz-plane and -48 and 48° with 2.9 and 3.0 dBi realized gain in the yoz-plane. Therefore, the proposed antenna is a good candidate for wireless communication systems.