Miniaturization of ESPAR Antenna Using Low-Cost 3D Printing Process

Abstract

In this paper, the miniaturized electronically steerable parasitic array radiator (ESPAR) antenna is presented. The size reduction was obtained by embedding its active and passive elements in polylactic acid (PLA) plastic material commonly used in low-cost 3D printing. The influence of 3D printing process imperfections on the ESPAR antenna design is investigated and a simple yet effective method to compensate them has been proposed. An antenna prototype was fabricated and measured, which showed that the experimental and simulated results are in good agreement. Realized antenna is characterized by 5.6 dBi peak gain and reflection coefficient of-17.6 dB. Base radius reduction of 23% and occupied area reduction of 40% were achieved.

Influence of Dielectric Overlay Permittivity on Size and Performance of Miniaturized ESPAR Antenna

“…Connecting each parasitic element to the SPDT switch allows one to change its Antenna size reduction is achieved by embedding all radiators in a cylindrical shaped dielectric overlay. This technique was proposed in [11] and adopted to the 3D print technology in [12]. In both cases, it provided satisfactory results, confirmed by realization and measurements.…”

“…5 for the reflection coefficient. Table I compares dimensions (in millimeters and free space wavelengths λ0) of three designed antennas with the standard-size [5] and PLA based [12] versions.…”

“…This article explores the possibility of further size reduction achieved by higher permittivity filaments than PLA and examines their influence on the antenna performance. The antennas have been designed to have their overlays fabricated in 3D print technology and air gaps between antenna elements and dielectric structure investigated in [12] were included. This feature allows for more realistic designs and improved agreement between simulation and measurement results.…”

“…Size of the ESPAR antenna is an important issue when integrating with WSN nodes and especially when it is dedicated for a drone of limited payload space. There is a number of papers concerning ESPAR antenna miniaturization [11], [12]. In [11] the authors achieved miniaturization by embedding antenna in a homogenous dielectric material.…”

“…In [11] the authors achieved miniaturization by embedding antenna in a homogenous dielectric material. The similar concept was employed in [12] to fabricate antenna at lower cost using 3D print technology. In order to manufacture dielectric overlay, cheap and common polylactic acid (PLA) filament of εr = 2.74 has been used resulting in 23% radius reduction.…”