• Journal of Advanced Navigation Technology
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• v.16 no.1
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• pp.35-40
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• 2012

In this paper, we present the size reduction method of HF whip antenna for ship communication. To reduce the size of the HF whip, the end part of linear whip is modified to helical type. We designed the whip antenna with 60% size of the commercial whip antenna and carried out communication experiments using the commercial and the designed whip antennas. From the experimental results, we found that the proposed whip antenna can replace the commercial whip antenna for ship communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.65-66
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• 2012

For HF antenna, whip antenna with 6m length or more has been used generally. In this paper, we suggest a new HF antenna which is smaller than commercial HF whip antenna. The shape of the proposed antenna is "ㄷ" and the size of the antenna is $1m{\times}2m$. The feature of the antenna has been simulated by NECWin tools.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1A
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• pp.41-46
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• 2003

A MF/HF marine whip antenna with side whips, which are connected at an angle with the straight main whip, has reported In this paper, the effects of side whips on the antenna are simulated by using NEC-WIN and a novel MF/HF ship antenna with side whips is designed First of all, the gain, return loss, and radiation pattern of the antenna on infinite perfect conductor plane are simulated as function of the parameters of the side whip, such as the number, the location, the length of the side whip and the angle with the main whip. After that, the size of the antenna is decided and set up on an experimental ship in Korea Maritime University. The antenna on the ship are simulated and the simulated input impedances are good agreement with the measured results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.178-182
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• 2003

In this paper, we designed a loading sleeve monopole operating at PCS and IMT-2000 frequency bands using the structure of the broadband loading sleeve monopole. The length of the designed antenna is lower than that of the helical antenna coupled with a whip used in commercial PCS handsets. The length and diameter of the designed antenna are 38 mm and 8 mm, respectively. The designed loading sleeve monopole is fabricated and investigated experimently. The VSWR is less than 1.5 in the PCS and IMT-2000 frequency bands(1750 MHz~2170 MHz) and gain is 3.5 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1095-1103
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• 1999

Presently, the retractable phone with a whip antenna composed of a helix and a monopole is most widely used for cellular mobile communications. However, since the length of the monopole is usually about λ/4, the strong radiated electric fields are produced in the region where the auricle of a head is contacted directly. This field distribution results in high specific absorption rates(SAR's) in the head. In this paper, SAR distributions and local SAR values for the inversely shaped phone(ISP) whose antenna arrangement is opposite to the original retractable phone(ORP) are compared with those for the ORP. This phone is accomplished by mounting the $\lambda$/4-whip antenna on the bottom, not on the top of the handset. The time-averaged field distribution in a computational space including a human model and a phone model is computed using the finite-difference time-domain(FDTD) method. SAR distributions and local SAR values for these phones are calculated with the field distributions. An anatomical head model and an approximate hand model were used to consider a real situation. From the analyzed data, it is shown that this arrangement of the antenna considerably reduces the spatial peak SAR in a human head.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.158-158
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• 2008

In general, a wireless communication device has employed a whip antenna or a stubby antenna. Recently, wireless communication device is increasingly employing an embedded antenna, Intenna, for the sake of miniaturization. Further, it may employ both external and embedded antennas. Examples of the embedded antenna include a multi-band monopole antenna, which radiates uniformly in all directions when viewed from above, and a planar inverted F antenna (PIFA), which is a variation of the monopole antenna. However, since the conventional antenna is mounted in a finished state on the mobile communication terminal, there is a limitation of space required for providing the antenna. According to the present study, there is provided an Intenna that is deposited on a front or back case of the mobile communication terminal by a sputtering method. Accordingly, it is possible to overcome a limitation of space required for providing the Intenna and to improve the performance of the Intenna formed on the front or back case of the mobile communication terminal.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.209-211
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• 2002

차량 탑재 FM 수신용 전 방향성 루프 안테나를 개발하였다. 2개의 수직 루프를 90도 교차하고, 1개의 수평 루프와 결합함으로써 전 방향 특성을 가질 수 있다. 또한 수직 및 수평편파 모두를 박기 때문에 도심 등 주위 환경변화에 따른 편파 다이버시티 현상도 제거한 수 있다. 10cm 직경의 19회 감긴 각 루프를 정합시키고 증폭하여, 90도 이상기와 함께 결합한 안테나를 개발하였다. FM 대역인 88-108MHz 대역에서 측정된 반사특성 및 패턴은 이론치와 잘 맞고 있으며, 기존 whip안테나 보다 평균 4dB 향상된 수신전력 특성을 보이고 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.40-45
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• 2007

Lightning warning system plays an important role in protecting human life and other facilities from lightning return strokes. This paper dealt with lightning positioning algorithms and circuits as a main function of lightning warning system, which monitor movements and activities of thunderclouds. Electric field component produced by lightning discharge is detected by the configuration of a whip antenna and a narrow-band resonance amplifier with center frequency of 300[kHz]. Measurement circuit of magnetic field waveform consists of a crossed-loop coil and an integral amplifier, and its frequency bandwidth is ranges from 5[kHz] to 1.2[MHz]. The polarity of lightning discharge is discriminated by electric field component. After-fixing the polarity, we can calculate the direction and distance of lightning discharge by the peak and the zero-cross time of magnetic field waveform.

• Journal of Astronomy and Space Sciences
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• v.29 no.1
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• pp.33-40
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• 2012

Triplet Ionospheric Observatory (TRIO) CubeSatforIon, Neutral, Electron MAgneticfields (CINEMA) is a CubeSat with the weight 3 kg that will be operated in the orbit conditions of about 800 km altitude and $90^{\circ}$ inclination angle, using the S-band and ultra-high frequency (UHF)-band communication frequencies. Regarding the communication antenna loaded on the satellite, the two patch antennas has the downlink function in the S-band, whereas the two whip antennas has the function to receive the command sent by the ground station to the satellite in the UHF-band. The uplink ground station that communicates through the UHF-band with the CINEMA satellite was established at Kyung Hee University. The system is mainly composed of a terminal node controller, a transceiver, and a helical antenna. The gain of the helical antenna established at the Kyung Hee University ground station was 9.8 dBi. The output of the transceiver was set to be 5 W (6.9 dB) for the communication test. Through the far-field test of the established system, it was verified that the Roman characters, figures and symbols were converted into packets and transmitted to the satellite receiver in the communication speed of 9,600 bps.

• Journal of Multimedia Information System
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• v.9 no.2
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• pp.145-154
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• 2022

The authors are making a prototype flexible board of a radio-frequency transmitter for measuring an electromyogram (EMG) of a flying moth and plan to apply for an experimental station license from the Ministry of Internal Affairs and Communications of Japan in the summer of 2022. The goal is to create a continuous low-dose exposure standard that incorporates scientific and physiological functional assessments to replace the current standard based on lethal dose 50. This paper describes the technical evaluation of the hardware. The signal of a bipolar EMG electrode is amplified by an operational amplifier. This potential is added to a voltage-controlled crystal oscillator (27 MHz, bandwidth: 4 kHz), frequency-converted, and transmitted from an antenna about 10 cm long (diameter: 0.03 mm). The power source is a 1.55-V wristwatch battery that has a total weight of about 0.3 g (one dry battery and analog circuit) and an expected operating time of 20 minutes. The output power is -7 dBm and the effective isotropic radiated power is -40 dBm. The signal is received by a dual-whip antenna (2.15 dBi) at a distance of about 100 m from the moth. The link margin of the communication circuit is above 30 dB within 100 m. The concepts of this hardware and the measurement data are presented in this paper. This will be the first biological data transmission from a moth with an official license. In future, this telemetry system will improve the detection of physiological abnormalities of moths.