A novel single probe-fed, single-layer, and single-patch triple-band microstrip antenna is presented. By incorporating two identical U-slots in the patch whose length is λd instead of 1/2λd in a conventional patch, three operating bands are achieved. Dual-beam radiation pattern is obtained at the upper band, and a single broadside beam radiation pattern is obtained at each of the lower and middle bands. The antenna's structure is simple. Only by using a single probe-fed point, the impedance matches well at all the three resonant frequencies. The measured and simulated results are in good agreement. The measured lower, middle, and upper bands are centered at 2.442 GHz, 3.505 GHz, and 5.787 GHz, respectively. The measured gains are 6.2 dBi at 2.442 GHz and 5.5 dBi at 3.505 GHz, respectively. At 5.787 GHz, the measured gains for the dual radiation beams are 8.4 dBi directed at 26° and 8.2 dBi directed at -38°, respectively. The proposed antenna can be a candidate for WLAN 2.4 GHz, WLAN 5.8 GHz, and 3.5 GHz of 5G (the fifth-generation mobile communication) operation.
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