Development of small-sized UWB antenna for binaural hearing AIDS

Abstract

This article introduces a new small-sized antenna designed and produced for application in wireless binaural hearing aids. Taking into consideration the antenna position and design of binaural hearing aids, we suggest two different types of small antennas. To reduce the size of both antennas, we used a slot structure and a high-dielectric constant material. The side that contacts the human skin was coated with a polydimethylsiloxane material that does not cause irritation even with long periods of usage. The proposed antennas were designed to be very small: the human-body-contact antenna is 4 x 3.2 x 0.201 mm, and the human-body-noncontact antenna is 4 x 4.5 x 0.735 mm. The two antennas operate at the center frequency of 8 GHz, and have an impedance bandwidth greater than 1 GHz. The characteristics of the return loss and radiation pattern were verified for these two antennas by performing the simulation using a three-dimension phantom, which applied the human electrical properties and practical tests, and the communication performance were verified through the S21 experiment. In addition, by performing the location-specific S21 experiment and comparing, the location with the best communication performance was determined. Experimental and simulation results in the Case 1 position showed excellent characteristics: the body-contact antenna exhibited -55.8 dB, and the nonbody-contact antenna exhibited -55.1 dB. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1883-1889, 2015