A Compact High-Efficiency Tri-Band CPW-Fed Millimeter-Wave Dielectric Patch Antenna for Wireless Systems

A low-profile tri-band millimeter-wave (mmWave) dielectric patch (DP) antenna (DPA) is proposed for fifth-generation (5G) and beyond wireless communication systems. Multiband operation is achieved by exciting the resonant ${\mathrm{TM}}_{11}$, ${\mathrm{TM}}_{31}$, and ${\mathrm{TM}}_{51}$ modes at approximately 22, 30, and 36 GHz, respectively. Crucially, these operating bands are strategically designed to align with essential mmWave communication standards: the 22 GHz band targets fixed short-range microwave backhaul links; the 30 GHz band services 5G New Radio (NR) n257/n258 allocations; and the 36 GHz band accommodates early 5G NR n260 spectrum requirements alongside emerging radar and sensing applications. The three modes are excited using a coplanar waveguide (CPW) feed structure. A prototype was fabricated and experimentally characterized, and its measured reflection coefficient, realized gain, and radiation patterns were compared with full-wave simulations. The proposed DPA exhibits an overall profile of $0.086{\lambda }_0$ while providing impedance bandwidths of $4.57\%$ ($21.4$–$22.4$ GHz), $4.24\%$ (30–$31.3$ GHz), and $2.75\%$ ($35.8$–$36.8$ GHz), together with simulated radiation efficiencies of $93\%$, $95\%$, and $95\%$ across the three respective bands. In addition, it delivers measured peak realized gains of $8.3$, $5.2$, and $4.3$ dBi at 22, 30, and 36 GHz, respectively. The proposed antenna combines tri-band coverage, a low profile, and high simulated efficiency in a single compact radiating element, making it a highly compelling candidate for modern compact multiband mmWave wireless system infrastructures.