volume | PIER Journals

Abstract

This work presents a modified, wide-band, bow-tie antenna integrated with a Frequency Selective Surface (FSS) designed to enhance gain and significantly reduce the Specific Absorption Rate (SAR). The proposed antenna, with a compact profile of 0.47λ_g × 0.77λ_g, operates at a center frequency of 2.4 GHz and exhibits a high radiation efficiency. By employing a flared polygonal radiating element, the antenna achieves wide-band performance across an operational spectrum of 1.97 GHz to 3.09 GHz, yielding a fractional bandwidth of 46.7%. An FSS array, functioning as a spatial filter, was designed and positioned 39 mm from the antenna, thereby forming an integrated system. Through numerical simulations, this system shows the gain improvement of the antenna from 2.51 dBi to 6.5 dBi and simultaneously reduces the SAR from 3.9 W/kg to 1.6 W/kg per 10 g of tissue, falling well below the permitted safety limit. The antenna and FSS array prototypes were fabricated and tested for scattering parameters, gain improvement, and radiation pattern. The measured results were in close alignment with the simulations, demonstrating the efficiency of the antenna for safe and high-performance off-body biomedical applications.

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Ms. Kesavalu Naidu Keerthi Naidu

Dr. Selvaraj Imaculate Rosaline