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 TM11, TM31, and TM51 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 0.086λ0 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.