Design of compact true wireless stereo (TWS) antenna in earphones for wearable communication applications

Abstract An ear-bar true wireless stereo (TWS) earphone antenna is designed and analysed to enhance the radiation efficiency, path gain with reduced specific absorption rate (SAR). The proposed design consists of a meander line structure printed on a flexible substrate of polyimide material. The antenna works for ISM band applications covering the frequency range 2.4–2.48 GHz with 80 MHz bandwidth. As the antenna is designed for earphone applications, it is simulated and measured inside the ear-bar for on body performance analysis yielding a gain value of 6.7 dBi. The individual design is placed inside the ear bar and attained a gain of 4.04 dBi. SAR analysis is carried out for investigating the radiated emissions of the proposed antenna and obtained the SAR of 0.707 W K −1 g −1 , when placed on the human body. As the designed antenna should exhibit binaural hearing, ear to ear (E2E) link analysis is carried out and path gain of −58 dB is estimated when the antenna is placed and analysed in both the ears.