Design of a Square Ring Patch Antenna with Metallized Grid for Monopolar Radiation Applications

This paper proposes the design of a semi-transparent square ring patch antenna that exhibits a monopolar radiation pattern. All metallic elements of the antenna are implemented using metallized grids, allowing most visible light to pass through the structure. The antenna operates without a substrate to significantly reduce losses and consists of a radiating layer formed by a square ring, fed by a central patch with a coaxial probe, and a ground plane. Both layers are short-circuited by four shorting walls made with grids, enabling the excitation of two conical radiation modes that, when coupled, result in wideband operation for the antenna. The antenna achieves monopolar radiation patterns over a bandwidth of 35%, with gains exceeding 4.5 dBi and transparency levels ranging from 65% to 80%, depending on the grid implementation and ground plane size. This proposed solution is designed for 3D printing of components and integration into vehicle windows or roofs.