Flexible fractal loaded patch antenna for wearable application

Abstract

This article presents the design of a compact, flexible Hilbert fractal-loaded antenna on curved patch geometry for a wearable non-invasive glucose monitoring device. The proposed FLCPA (Fractal Loaded Curved Patch Antenna) design consists of a curved fractal-filled radiating element, defective ground plane and microstrip feedline. The design is fabricated using a flexible polyimide substrate with a thickness of 0.25 mm. The antenna operates in 2.45GHzISM, Wi-Max (3.6–3.8 GHz) and portions of UWB (3.61 GHz to5.28 GHz) with dimensions of 17 × 25 × 0.25 mm³. The proposed antenna structure has been simulated using ANSYS HFSS and fabricated results are tested using an Agilent vector network analyser (VNA) and Anchoic chamber. The experimental results show that the antenna works well for wearable application working in the ISM band with a gain of 2.5dB and radiation efficiency of 75.6%. The operational bands covering the bandwidth of 1670 MHz and 220 MHz on analysing the design over a human phantom model, it is clear that the design is well suitable for application in diagnostic health monitoring systems. Also, the proposed system leverages the principles of electromagnetic wave propagation through human Finger tissues, providing a reliable and convenient alternative to conventional invasive methods. Simulated analysis made on the thumb finger phantom designed in the HFSS environment and the variations in the frequency shift for different glucose concentration were observed.