• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.666-670
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• 2015

This paper presents radiation pattern reconfigurable antenna for Fitbit Flex wristband which detects vital signal. Also, the paper presents Specific Absorption Rate (SAR) from the loop-dipole radiation pattern reconfigurable antenna based on the position of human body. The proposed loop-dipole radiation pattern reconfigurable antenna produces two opposite side direction radiation pattern using two RF switches. The resonant frequency of the radiation pattern reconfigurable antenna is Bluetooth communication bandwidth (2.4 - 2.485 GHz) and the maximum gain of the proposed antenna is 1.96 dBi. The proposed antenna satisfied the standard SAR value of 1.6 W/kg in 1 g tissue of the human body when the Bluetooth communication input average power of 0.04 W is excited to five parts of human body (head, chest, stomach, back, wrist). The maximum SAR value of in this simulation is presented in the part of head.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1095-1103
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• 2014

WBAN has received great attention recently due to its versatile applicability. In this paper, antennas suitable for WBAN communication depending on the locations of mobile devices and the manufacturing of a human equivalent phantom are introduced. The effect of the body on the communication performance is largely dependent on the locations of devices. Specifically, the radiation and return loss characteristics of the antenna are greatly influenced by the characteristics of a medium existing in the near-field of an antenna. Thus, the proper WBAN antenna design is important in establishing a successful communication link between the transceivers. To consider the effect of the body on the antenna performance, the human equivalent phantom is also important factor in the WBAN antenna design and measurement. In introduction, categorization of the WBAN communication channel is introduced and antenna characteristics required for each communication channel are described. In the main subject section, several WBAN antenna design examples along with the implementation of the human equivalent phantom are discussed. In conclusion, the factors, which have to be considered in the design process, and future research are mentioned.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1107-1115
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• 2011

In this paper, a headset multiple-input multiple-output(MIMO) antenna for on-body application is proposed and the antenna performance with body effect and the impact on human body are investigated. The proposed MIMO antenna is composed of two planar inverted-F antennas(PIFA) above ground plane and an isolator located between the two antennas enhance the isolation characteristic. Simulation was carried to analyze the effect of human body on antenna performance when a human body is located in the near field of the antenna. According to the measurement result, the diversity performance of the proposed antenna can be considered good since ECC(Envelope Correlation Coefficient), which commonly indicates the performance of a MIMO antenna, remains below 0.1 over the ISM band. The measured SAR values for antennas 1 and 2 are 0.575 W/kg and 0.571 W/kg, respectively when 250 mW input power in engaged. These values satisfy the FCC guideline which states that the 1-g average SAR should be lower than 1.6 W/kg.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.314-319
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• 2012

In this paper, a repeater antenna operating at MICS and ISM bands is proposed and the antenna performance including the human body effect is investigated. The proposed antenna is composed of a ZOR(Zeroth Order Resonator) and a loop antenna. A loop antenna is operated at ISM band and a loop antenna capacitively coupled with a ZOR acts as an antenna for MICS band. Simulation was carried out in order to analyze the effects of human body on antenna performance when a human body is located in the near field of an antenna. According to the simulated and measured results, the proposed antenna has -10 dB $S_{11}$ bandwidth wide enough to cover both MICS and ISM bands. The measured peak gains are -28.53 dBi and 3.85 dBi at MICS and ISM band, respectively. The dual band and radiation properties of the proposed antenna are well suited for the WBAN repeater system.

• Journal of electromagnetic engineering and science
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• v.15 no.2
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• pp.97-103
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• 2015

This paper investigates the effect of absorption loss by a human body to the received signal strength with respect to on-body transmitting antenna positions in on-to-off wireless body area networks. This investigation is based on measurement results obtained from experiments performed on human bodies (male and female) using planar inverted-F antennas in an anechoic chamber. The total absorption loss by the human body is also presented through the SEMCAD-X simulations. Our investigation showed that the received signal strength becomes lower when the transmitting antenna is mounted at a specific position where more absorption loss is experienced. The statistical analyses of on-to-off body channel characteristics based on the measurement results are presented.

• 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.

• Journal of Advanced Navigation Technology
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• v.26 no.1
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• pp.9-14
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• 2022

In this paper we investigate the advantages when the GPS Antenna is installed on the rear missile body. In conventional design the GPS antenna locates on the front part of missile. However it causes degraded GPS positioning performance since the missile body blocks the GPS signals. This paper proposes the GPS array antenna design which locates on the rear part of missile body and has the tilted antenna patches to achieve the maximum area of receiving GPS signals. We simulate LOS region of receiving signals and conducted anechoic chamber test to define the effective signal receiving region. And we conduct field test and flight test to check out the enhancement of signal receiving area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.727-732
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• 2008

Recently, according to the increase of using the microwave equipments, the interests in effects on human body have been also increased. For example, there have been many researches on making the standard the specific absorbing ratio (SAR) caused by mobile phones. However, it is needed to study on the induced current on human body caused by HF(Hight Frequency) band which can deeply penetrate the human body. Especially, since the RFID systems are applied to the transportation card and the library, it is hooded to research on the effect on human body exposed to the radiated power from the RFID system. In this paper, we designed a cylindrical monopole antenna model of human body exposed to 13.56 MHz RFID system, which can model the induced current on human body. To verify the proposed equivalent antenna model, we compared the induced currents between human body and the equivalent antenna model.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.763-770
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• 2021

In this paper, in order to exclude the influence of BAN(Body Area Network) signals operating in the ISM band, the design and optimization process of an on-body microstrip patch antenna operating at 4.567 GHz is presented. The antenna for the monitoring of the lower legs with cancellous osteoporosis is designed to be lightweight and compact with improved return loss and bandwidth. The structure around the applied lower leg consisted of a five-layer dielectric plane. Taking into account losses, the complex dielectric constant of each layer is calculated using multi Cole-Cole model parameters, whereas a unipolar model is used for normal or osteoporotic cancellous bones. The return loss of the coaxial feed antenna on the phantom is -67.26 dB at 4.567 GHz, and in the case of osteoporosis, at the same frequency the return loss difference is 35.88 dB, and the resonance frequency difference is about 7 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.518-525
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• 2005

In this paper, radiation patterns are simulated and analyzed for inverted-F antenna(IFA) on a cylindrical conducting body like a satellite launcher. First, parametric studies are performed for IFA itself to analyze its characteristics. Then, IFAs on a cylindrical conducting body are simulated and analyzed. Especially, by changing the number of IFAs, the length and the diameter of the cylinder radiation patterns are simulated and analyzed. Finally, IFAs on a cylindrical conducting body are fabricated and their return losses and radiation patterns are measured. Good agreements are observed between the simulated and measured results.