Design and Simulation of a Compact Triple-Band Patch Antenna for Sub-6 GHz and Millimetre-Wave Applications

This paper presents a simulated compact triple-band patch antenna for 5G and millimetre-wave applications. The antenna is designed on a Rogers RO3003 substrate with compact dimensions of 10 mm × 25 mm. The proposed structure employs a rectangular patch, a diamond-shaped slot, and a defected ground plane to achieve triple-band resonance. The antenna operates at 3.5 GHz (sub-6 GHz), 23 GHz (candidate millimetre-wave band), and 38 GHz (millimetre-wave band). Simulated −10 dB impedance bandwidths are 3.35–3.72 GHz (0.37 GHz, 10.6%), 22.1–24.3 GHz (2.2 GHz, 9.6%), and 37.2–39.1 GHz (1.9 GHz, 5.0%). The simulated peak gains are 2.46 dBi, 5.83 dBi, and 5.35 dBi at the three bands, respectively. The radiation patterns are stable in simulation. The 23 GHz resonance is a candidate millimetre-wave band and only partially overlaps the lower edge of the 24.25–29.5 GHz 5G range; therefore, it should not be described as full 5G NR coverage without retuning. A comparative analysis with recent literature shows competitive performance in terms of size, gain, and multiband coverage. However, all results are simulation-based and require experimental validation.