Tri-Band Circular Microstrip Patch Antenna with Slits and Multilayered Substrate for 5G mmWave Communications

This paper presents a compact tri-band microstrip patch antenna for 5G mmWave and WiGig applications, featuring a circular patch with dual symmetrical slits on a three-layer substrate. The stacked configuration combines Rogers RT/Duroid 5880 (εr = 2.2, tanδ = 0.0009, 0.2 mm of thickness) as top and bottom layers and Taconic RF-43 (εr = 4.3, tanδ = 0.0033, a thickness of 0.2 mm) as the middle layer, yielding a 0.6 mm total substrate thickness. The 10×10×0.6 mm³ design with a full ground plane achieves tri-band operation at 28.3 GHz (27.12–29.42 GHz, 2.3 GHz BW), 41.5 GHz (40.1–48.21 GHz, 8.11 GHz BW), and 61.6 GHz (55.24–66.27 GHz, 11.03 GHz BW), covering n261 (27.5–28.35 GHz), n262 (47.2–48.2 GHz), and WiGig (57–64 GHz) bands. Simulations in CST Studio Suite reveal peak gains of 7.05 dBi, 7.28 dBi, and 6.39 dBi at the three frequencies, with radiation efficiencies exceeding 80%, peaking at 91%. Performance validation includes reflection coefficients <-16.28 dB, VSWR 1.04–1.36, and stable impedance matching across all bands. The antenna's low-profile geometry, broad bandwidth, and high-efficiency address key mmWave challenges, making it suitable for 5G backhaul, IoT, and short-range communications. Its compatibility with emerging standards and cost-effective fabrication potential underscores its viability for next-generation wireless systems.