Design and Bending Analysis of Wearable Compact Patch Antenna for Medical Telemetry Based on Flexible Material

A comprehensive study of compact flexible patch antenna, which is the suitable topology for medical telemetry operated in the industrial scientific and medical (ISM) band, is presented. For establishing efficient wireless links for assisting medical diagnostics, the antenna is required to be of a low profile, safe, and simple geometry. To achieve the compactness of the structure, Taguchi’s optimization method has been applied based on the concept of orthogonal array. The designed antenna uses two distinct flexible substrates, namely polyethylene terephthalate (PET) with dimension 43.5x36.89x0.175 mm 3 , and Rogers RT/Duroid 5880 with dimension 48.5x49.66x1.58 mm 3 categorized under materials, namely plastic and circuit (microfiber reinforced PTFE) material respectively. The approach has been demonstrated for a simple, compact flexible antenna with reduced dimension by 5.37% for PET, and 23.96% for RT 5880 as compared to the conventional rectangular patch design parameters. The resonant frequencies of the designed antennas are 2.435 GHz and 2.45 GHz for PET, and Rogers RT/Duroid 5880, respectively, with a bandwidth of 73.2MHz for RT/Duroid, and 16.8 MHz for PET. The maximum observed directivity of the proposed antenna using PET and Rogers RT/Duroid 5880 are 5.15 dBi, and 6.117 dBi, respectively, at 2.45 GHz. Furthermore, characterization for performance variation is carried out through bending analysis for different curvatures and Specific Absorption Rate (SAR) analysis in order to demonstrate its suitability for direct integration with wearable biomedical sensing chips used for medical telemetry.