Antenna design using speaker wire for a Bluetooth ear set

Abstract

In this article, an antenna design using an audio wire is proposed for a compact Bluetooth ear set. The length of the audio wire is less than a quarter of a wavelength in Bluetooth ear sets. Therefore, an appropriate feed structure needs to be designed to utilize the wire as an antenna. The antenna has been tuned using an inductor and impedance matching is accomplished by a loop‐type feeding structure with lumped capacitors. The feeding structure can be used to tune various lengths of the antenna. Full wave simulations are conducted to observe the effectiveness of the proposed technique. The measured and simulated bandwidths of the antenna are in good agreement. The measured bandwidth and average efficiency of the antenna were 116 MHz and 54.74%, whereas the average total isotropic sensitivity was 80.12 dBm that comply with the desired criteria for operation of the Bluetooth ear set.

A Chip Antenna for Bluetooth Earphones with Cross-Head Interference Tested from Received-Signal Sensing

“…Many researchers have addressed body-centric connectivity with phones, goggles, watches, and tags on conductive textiles, but few have handled antennas for head-sets or ear-sets or earphones, supposed that they are relatively thin and small. An ear-set is observed in the title of Z. Zahid et al’s work, where they took advantage of speaker wires for their antenna [ 19 ]. Their antenna necessitates its own PCB for feeding and ground, which has no choice but to exist outside of the ear-set, which is not appealing to realistic prototyping.…”

An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing

“…Many researchers have addressed body-centric connectivity using phones, goggles, watches, and tags on conductive textiles, but few have handled antennas for headsets or earphones, supposing that they are relatively thin and small. An ear-set was spotted in the title of Zahid et al's work, where they took advantage of speaker wires for their antenna [24]. Their antenna necessitated its own PCB for feeding and grounding, forcing its existence outside of the ear-set, which is not appealing for realistic prototyping.…”

Over-the-Air Evaluation of User Body Loss for Popular In-Ear Bluetooth Earbuds

“…Investigations of the user impact on body-worn antennas have also been conducted [11,[15][16][17]. A few studies on headset performance as well as antenna design for applications, such as headsets and hearing-aids, have also been reported [5,6,13,[18][19][20][21][22][23][24][25].…”