• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.372-377
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• 2016

Communication flow is changing rapidly. Recently, a range of wearable devices such as wearable glasses and wearable watch, have been launched. These kinds of wearable devices help people to live a more comfortable life. Wearable devices most have an antenna for wireless communication. This paper reports a transparent antenna that is made of an optically transparent material for wearable glasses. Transparent antenna can be applied to smart windows and will not disturb the view of user. IZTO/Ag/IZTO multilayer electrode has higher electrical and optical properties. This antenna is available because of its good electrical properties. This study measured the performance of the proposed transparent antenna, which is made of a multilayer electrode, applied to a lens. The proposed antenna was simulated with several substrates. The antenna impedance was matched with length and width of the antenna. The antenna's conductivity and transparency was measured using a HMS-3000 and UV-spectrometer. A 40nm thick Ag single layer antenna was fabricated on a flexible polyimide substrate for comparing the antenna performances. The fabricated antenna is useable at a frequency of 2.4-2.5GHz, which is suitable for Wifi communications and has peak gain of 2.89dBi and an efficiency of 34%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.16-23
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• 2015

In this paper, a bent microstrip patch antenna, which is suitable for band-type wearable devices and RF configuration, to be used in the WCDMA2100 mobile network is proposed. The proposed antenna using RF configuration which is consisted of separated Tx and Rx frequency band is designed to operate or function in WCDMA2100 Tx frequency band only and it is not strongly affected by the human body because of the conductor at the bottom side. At both flat case and bent case, the proposed antenna's maximum gain satisfies at least 5.3 dBi, and its -6 dB return loss bandwidth is wider than 20 MHz. The simulated surface absorption rate($SAR_{1g}$) result is under 0.7 [W/kg]. The proposed antenna suits in band-type wearable devices which is worn on wrists or arms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2770-2776
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• 2015

The development of efficient wearable antennas is required to implement short range body-centric wireless communication links for various internet of thing applications. We present simulation and measurement results of conductive-fiber-based wearable antennas which can comfortably fabricated directly on usual clothing materials. The proposed antenna is a form of a rectangular patch antenna designed by weaving conductive fibers on a felt substrate. A full-wave electromagnetic simulation tool is used to investigate the antenna performance such as antenna impedance, resonant frequency, and radiation efficiency. Parametric studies show that the radiation efficiency increases from 67.5% to 70.4% by widening the gap between conductive fibers from 0.25mm to 3mm. This implies a wearable antenna with good radiation efficiency can be designed despite of less portion of conductive fibers on the antenna. The simulation results are also verified by measured results with fabricated antennas.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.317-328
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• 2017

This paper presents design and specific absorption rate analysis of a 2.4 GHz wearable patch antenna on a conventional and electromagnetic bandgap (EBG) ground planes, under normal and bent conditions. Wearable materials are used in the design of the antenna and EBG surfaces. A woven fabric (Zelt) is used as a conductive material and a 3 mm thicker Wash Cotton is used as a substrate. The dielectric constant and tangent loss of the substrate are 1.51 and 0.02 respectively. The volume of the proposed antenna is $113{\times}96.4{\times}3mm^3$. The metamaterial surface is used as a high impedance surface which shields the body from the hazards of electromagnetic radiations to reduce the Specific Absorption Rate (SAR). For on-body analysis a three layer model (containing skin, fats and muscles) of human arm is used. Antenna employing the EBG ground plane gives safe value of SAR (i.e. 1.77W/kg<2W/kg), when worn on human arm. This value is obtained using the safe limit of 2 W/kg, averaged over 10g of tissue, specified by the International Commission of Non Ionization Radiation Protection (ICNIRP). The SAR is reduced by 83.82 % as compare to the conventional antenna (8.16 W/kg>2W/kg). The efficiency of the EBG based antenna is improved from 52 to 74 %, relative to the conventional counterpart. The proposed antenna can be used in wearable electronics and smart clothing.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.522-528
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• 2017

In this paper, we propose a multi-band antenna for wearable devices using metal frame coupling. The proposed antenna has a $45mm{\times}35mm$ antenna using metal frame and a ground dual coupling structure. The proposed multi-band antenna in this paper is optimized for small devices such as wearable devices. By using the metal frame as a part of the antenna, the volume of the antenna is reduced and satisfies under VSWR 3:1 impedance bandwidth of 70 MHz (870 ~ 940 MHz) in low frequency band, 280 MHz (1600 ~ 1880 MHz) and 280 MHz (1900 ~ 2170 MHz) in high frequency band. It also verified the applicability of wearable devices by measuring wireless performance indicators such as TRP/TIS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.10-15
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• 2017

Research interest has strongly focused on developing a method for effectively transmitting bio-signals over a distance using a wireless wearable device. In this paper, we describe a procedure for the design and fabrication of a wearable antenna based on embroidering conductive threads to clothing capable of transmitting electrocardiogram signals. 3D electromagnetic simulation software and embroidery software were used to design and fabricate the conductive thread-based antenna, respectively. The measurement results show that the reflection coefficient of the fabricated antenna prototype exhibits excellent antenna impedance matching characteristics of less than -10dB in the Zigbee 2.4GHz frequency band. We also verified that the electrocardiogram data could be effectively received and monitored in real-time by a receiver 220m away from the transmitter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.1-6
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• 2008

A wearable T-matching dipole UHF RFID tag antenna has been designed using conductive electro-thread. The conductivity of the electro-thread has been measured depending on the number of twisted thread. The measured conductivity has been used for simulation to have accurate simulation results. The flexible electro-thread or fabric has been used for fabricating the antenna instead of using copper tape since the electro-thread is more flexible and wearable than copper tape. The return loss and reading range of the fabricated electro-thread UHF RFID tag antennas have been tested. The reading range is approximately 2.4 m.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.623-627
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• 2014

In recent years, wireless communication technologies in human body have received an increasing attention and the research on an antenna that can be worn also has been actively conducted. In this paper, an wearable antenna that can receive GPS signal frequency is proposed. The antenna was manufactured by using a copper polyester fabric with thickness of 0.08mm as a radiator and a ground plate, and a goatskin with thickness of 0.7mm as dielectric substrate. Cutting edges placed in diagonal direction of square patch in order to obtain a circular polarization characteristic, and the conductive cloth and leather was laminated by using a conductive epoxy. First, goatskin dielectric constant was obtained through the simulation and measurement of resonance frequency of the three square patch antennas with different size. On the basis of the results, an antenna operating in the GPS band was designed and the performance of the antenna was validated by making the experiment. The change of the characteristic of the antenna that is located on the shoulder parts of the clothing and wearing person were measured. And it was confirmed that the reception sensitivity has a similar level as compared to the commercially produced ceramic GPS antenna.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.155-160
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• 2021

In this paper, we investigated the aptness of embroidered textile dipole antenna as a wearable antenna. We designed an 2.45GHz ISM band embroidered textile dipole antenna on polyester textile. We investigated its characteristics depends on 3 variables, thickness of textile(ttextile), distance between textile and surface of body(gbody) and conductance of surface of body(𝜎body). Thickness of textile(ttextile) was affecting on the antenna resonance frequency(fo). As the conductance of surface of body(𝜎body) was increased the antenna resonance frequency(fo) and the antenna gain were increased slightly. The increment of the distance between textile and surface of body(gbody) caused relatively large increment of the antenna resonance frequency(fo) and the antenna gain. From the results, in the case of designing an embroidered textile dipole antenna as a wearable antenna we should consider carefully the two variables, distance between textile and surface of body(gbody) and thickness of textile(ttextile). Due to its large variation, the distance between textile and surface of body(gbody) may be a technical barrier in designing embroidered textile dipole antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1071-1076
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• 2009

A wearable embroidery 'ㅂ' character shape UHF RFID tag antenna has been designed using conductive electro-thread. After testing characteristics of various electro-threads, the embroidery tag, with a T-matching structure, has been designed on a cloth with 200D(denier) electro-thread which performs electrically better. The embroidery tag on a piece of fabric or clothes made with the flexible electro-thread is a wearable tag and possible to be recognized by an RFID system. The conductivity of different deniers of electro-threads has been measured. The measured conductivity has been used for simulation and fabrication to have accurate simulation results. To verify the characteristics of the tag antenna, the return loss and reading range of the fabricated embroidery electro-thread UHF RFID tag antenna have been tested. The reading range is approximately 1.52 m.