An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing
In this paper, a novel thin and flexible antenna is proposed for earbuds to gain an improvement in their wireless signal-sensing capability as a film-based artificial magnetic conductor (AMC) structure. As antenna designs for earbuds face challenges of being embedded beneath the top cover of the ear...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-06-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/12/4523 |
| _version_ | 1827656668355231744 |
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| author | Yejune Seo Inyeol Moon Junghyun Cho Yejin Lee Jiyeon Jang Morimoto Shohei Kurosaki Toshifumi Sungtek Kahng |
| author_facet | Yejune Seo Inyeol Moon Junghyun Cho Yejin Lee Jiyeon Jang Morimoto Shohei Kurosaki Toshifumi Sungtek Kahng |
| author_sort | Yejune Seo |
| collection | DOAJ |
| description | In this paper, a novel thin and flexible antenna is proposed for earbuds to gain an improvement in their wireless signal-sensing capability as a film-based artificial magnetic conductor (AMC) structure. As antenna designs for earbuds face challenges of being embedded beneath the top cover of the earbud, conformal to curved surfaces, and very close to metallic ground and touch-panel parts, as well as scarce degrees of freedom from feeding conditions and functional degradation by human tissue, unlike conventional techniques such as quasi quarter-wavelength radiators on LDS and epoxy molding compounds (relatively thick and pricy), an antenna of a metal pattern on a film is made with another film layer as the AMC to mitigate problems of the antenna in a small and curved space of an insert-molded wireless device. The antenna was designed, fabricated, and embedded in earbud mockups to work for the 2.4 GHz Bluetooth RF link, and its functions were verified by RF and antenna measurement, showing that it could overcome the limitations in impedance matching with only lumped elements and poor radiation by the ordinary schemes. The input reflection coefficient and antenna efficiency were 10 dB and 9% better than other methods. In particular, the on-film AMC antenna (OFAA) presents robustness against deterioration by the human tissue, when it is placed in the ear phantom at the workbench and implemented in an in situ test using a large zorb ball mimicking a realistic sensing environment. This yielded an RSSI enhancement of 20–30 dB. |
| first_indexed | 2024-03-09T22:31:34Z |
| format | Article |
| id | doaj.art-193b5de98f7141879a0162664a49ed6b |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T22:31:34Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-193b5de98f7141879a0162664a49ed6b2023-11-23T18:54:45ZengMDPI AGSensors1424-82202022-06-012212452310.3390/s22124523An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal SensingYejune Seo0Inyeol Moon1Junghyun Cho2Yejin Lee3Jiyeon Jang4Morimoto Shohei5Kurosaki Toshifumi6Sungtek Kahng7Department of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaDepartment of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaDepartment of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaDepartment of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaDepartment of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaNISSHA Co., Ltd., 3 Mibu Hanai-Cho, Nakakyo-ku, Kyoto 604-8551, JapanNISSHA Co., Ltd., 3 Mibu Hanai-Cho, Nakakyo-ku, Kyoto 604-8551, JapanDepartment of Information & Telecommunication Engineering, Incheon National University, Incheon 22012, KoreaIn this paper, a novel thin and flexible antenna is proposed for earbuds to gain an improvement in their wireless signal-sensing capability as a film-based artificial magnetic conductor (AMC) structure. As antenna designs for earbuds face challenges of being embedded beneath the top cover of the earbud, conformal to curved surfaces, and very close to metallic ground and touch-panel parts, as well as scarce degrees of freedom from feeding conditions and functional degradation by human tissue, unlike conventional techniques such as quasi quarter-wavelength radiators on LDS and epoxy molding compounds (relatively thick and pricy), an antenna of a metal pattern on a film is made with another film layer as the AMC to mitigate problems of the antenna in a small and curved space of an insert-molded wireless device. The antenna was designed, fabricated, and embedded in earbud mockups to work for the 2.4 GHz Bluetooth RF link, and its functions were verified by RF and antenna measurement, showing that it could overcome the limitations in impedance matching with only lumped elements and poor radiation by the ordinary schemes. The input reflection coefficient and antenna efficiency were 10 dB and 9% better than other methods. In particular, the on-film AMC antenna (OFAA) presents robustness against deterioration by the human tissue, when it is placed in the ear phantom at the workbench and implemented in an in situ test using a large zorb ball mimicking a realistic sensing environment. This yielded an RSSI enhancement of 20–30 dB.https://www.mdpi.com/1424-8220/22/12/4523earphonewearable antennaAMC antennametamaterial structurereceived signal strength sensinghead–ear phantom |
| spellingShingle | Yejune Seo Inyeol Moon Junghyun Cho Yejin Lee Jiyeon Jang Morimoto Shohei Kurosaki Toshifumi Sungtek Kahng An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing Sensors earphone wearable antenna AMC antenna metamaterial structure received signal strength sensing head–ear phantom |
| title | An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing |
| title_full | An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing |
| title_fullStr | An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing |
| title_full_unstemmed | An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing |
| title_short | An On-Film AMC Antenna Insert-Molded in Earbuds with Enhancement in In-Ear and In Situ Received-Signal Sensing |
| title_sort | on film amc antenna insert molded in earbuds with enhancement in in ear and in situ received signal sensing |
| topic | earphone wearable antenna AMC antenna metamaterial structure received signal strength sensing head–ear phantom |
| url | https://www.mdpi.com/1424-8220/22/12/4523 |
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