A compact conductor-backed CPW-fed patch antenna for multi-band wireless applications

This paper presents a novel conductor-backed coplanar waveguide (CB-CPW)-fed asymmetric cross-shaped patch antenna, engineered for multi-band operation across contemporary and future wireless standards. The design is realized on a low-cost FR4 substrate with a compact physical size of 30 × 30 mm 2 (0.28λ₀ × 0.28λ₀ at 2.8 GHz). Through a systematic evolutionary design process incorporating ground-connected strips and backside square grounds, the antenna achieves multi-resonant behavior. Simulation results indicate three primary resonances at 3.25, 5.06, and 10.95 GHz with reflection coefficients below −41 dB. Experimental measurements on the fabricated prototype demonstrate robust performance with impedance bandwidths (|S₁₁|≤ −10 dB) covering 2.8–5.4 GHz (63.1% FBW) for IMT, WiMAX, WLAN, and WAIC; 5.9–7.8 GHz (29.82% FBW) for 5G NR; and 10.5–12.6 GHz (18.1% FBW) for mid-band 6G applications. The measured peak gain is 3.9 dBi, with a radiation efficiency of up to 61%. The antenna exhibits stable radiation patterns across the bands. The strong agreement between simulation and measurement, despite minor shifts attributed to fabrication tolerances and feed parasitics, validates the design as a compact, cost-effective, and promising solution for modern multi-band portable devices.