A Curved Microstrip Patch Antenna Designed From Transparent Conductive Films

Abstract

Transparent microstrip patch antennas suffer from low radiation efficiency and gain when manufactured using transparent conductive films (TCFs), mainly at low frequency (starting from the microwave S band). To address this problem, we propose a curved microstrip patch antenna designed using transparent materials. This new configuration has proven to be a simple and effective solution to improve the radiation efficiency and gain of TCF printed antennas. In fact, when typical values of the TCF surface resistance are considered (between 2 and 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> /sq), the new antenna features a radiation efficiency of up to 72.3% and a realized gain of up to 5.3 dBi at 2.15 GHz, with a significant improvement in comparison with the flat transparent microstrip antenna (up to 17.7% radiation efficiency, and 0.5 dBi realized gain). Good transparency and lightweight is ensured by the deposition of the TCF on a polyethylene terephthalate film, which lies, in turn, on a 3D-printed curved polyethylene terephthalate glycol supporting frame. Simulations using Ansys HFSS are presented to demonstrate the potential of the proposed configuration. Then, a prototype of the transparent curved patch antenna is fabricated and measured to assess the simulated results.