A Low-Cost 3D-Printed Broadband Sinusoidal-Shaped Patch Antenna With Coplanar Microstrip Feed

Abstract

This paper introduces an advanced architecture for wideband microstrip patch antennas (MPAs) that addresses the intrinsic limitations of narrow impedance bandwidth and significant feed-line losses associated with thick dielectric substrates. The proposed solution integrates two primary innovations: a sinusoidal vertical patch profile, enabled by precision 3-D printing, and a locally hollowed substrate for active loss mitigation. Unlike traditional designs that utilize a uniformly thick dielectric to maximize bandwidth at the expense of efficiency, this approach confines the supporting material strictly to a thin dielectric layer beneath the radiating patch. This structure significantly reduces dielectric losses and suppresses surface wave excitation along the coplanar microstrip feed line. Leveraging this 3-D geometry, wideband impedance matching is achieved using a single open-ended stub integrated within the hollowed region. Experimental results demonstrate a fractional impedance bandwidth exceeding 26.5%, representing a 40% improvement over state-of-the-art coplanar-fed designs and reaching performance levels comparable to more complex, less-integrable coaxial probe-fed antennas. Furthermore, the 3-D curvature effectively reduces the antenna projected resonant size, providing a compact footprint ideal for the high-density integrated circuits of modern communication systems.