Printed flexible wideband microstrip antenna for wireless applications

Abstract

Recently, paper has been mentioned in many research studies [1-4] as a good choice of a substrate material for flexible electronics. In this paper, the E4D paper has been characterized by the cavity perturbation method, then a monopole antenna structure, called “Sapin” by its shape, has been designed on it to cover a very wide frequency range including two WLAN bands. The proposed antenna is rather compact with the dimensions of 45 × 28 mm2 with good matching characteristics. The simulated return loss is over 35 dB at 2.45 GHz, over 20 dB at 5.5 GHz. Especially, this antenna has quite large bandwidth, from 2.2 GHz to over 10 GHz and nearly omnidirectional radiation patterns at 2.45 GHz while a little more directive at 5.5 GHz. Six prototypes have been fabricated on 104-μm-thick E4D paper by screen printing technology in order to verify the stability of measurement results. They are thin and flexible that can be attached to a box with various shapes. The simulation and measurement results, which showed rather good agreement, confirmed a good performance of the designed antenna.