• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1097-1106
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• 2009

In this paper, the cross monopole antenna with branch element is presented and its radiation characteristics are investigated. To confirm the broadband characteristics of the proposed antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in PCS, WCDMA, WiBro and S-DMB band(1.750~2.655 GHz). It is shown that the designed antenna has the non-directional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5 and gain over 1.9 dBi in 1.72~2.82 GHz. From these results, the presented antenna is conformed as a broadband antenna which can be used for PCS, WCDMA, WiBro and S-DMB band.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.249-254
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• 2014

We have studied on the possibility of railway stability system using RFID tag. UHF RFID tag was desinged, manufactured and tested. Proposed UHF tag antenna has PIFA type structure and inset feed multi matching technique was attempted for impedance matching of antenna. The impedance bandwidth (VSWR < 3) of the proposed tag antenna covers 917~923 MHz. Measured peak gain is 3.225 dBi and UHF band with an omni-directional radiation pattern. RFID reader and tag installed in motor car and track, respectively. Then, tag recognition rate according to velocity of car (under 45 km/h) represented 100 %.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.343-348
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• 2019

In this paper, a dual-band antenna is proposed for the autonomous vehicle as well as omni-directional. The proposed antenna operates in the 4G/LTE band (1,710~2,170MHz) and 5G/NR band (3,400~3,700MHz). In order to obtain the dual-band operation, the planar monopole antenna is proposed as the novel structure with single port of the 50ohm. To give the properties of dual-band, an additional antenna element with slit was added to the planar monopole antenna, and then a structural adjustment parameter was optimized for achieving the target performance in bands. The planar monopole antenna in the LTE band acts as the coupled feed for the added parasitic radiator in the 5G NR band. The proposed antenna has $38.5{\times}36.0{\times}1.0[mm^3]$ on a ground with diameter of 96mm. From the fabrication and measurement results, the impedance bandwidth (VSWR<2) of the proposed antenna covers 1,480~2,260MHz (LTE band: 1,710~2,170MHz) and 3,310~3,930MHz (5G NR band: 3,400~3,700MHz). The proposed planar monopole antenna also obtained the measured gain and radiation pattern of omni-directional radiation pattern in the anechoic chamber.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4537-4542
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• 2010

In this paper, the antenna radiation pattern inside the vehicle is presented for observing the change occurring in non-anechoic environment using monopole antenna. The environment for radio communication can be affected by antenna characteristic variation inside the small space existing multi reflection waves. To perform simulation and measurement about antenna radiation pattern, the radio frequency bands for GPS and Wibro services expected to use inside the vehicle is selected. The simulation is based on the ray-tracing method and the radiation pattern is measured inside the vehicle and in free space using monopole antenna having those frequency bands. In accordance with the measurement and simulation results, when two antennas are put inside the vehicle, the omni-directional characteristic of the antenna is maintained but the received power is increased than free space case and the difference between the each case of measurements is increased as the operating frequency is increased.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.9
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• pp.922-927
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• 2009

The transducers used in active sonar on surface ships are packed in a specific geometry in the array drum in order to meet the requirements such as the source level, directional beam pattern, etc. This paper describes the acoustic characteristics of the cylindrical array which is based on a 64 vertical staves arrangement, each stave composed 5 independent transducers. Firstly, the single transducer on the rigid baffle in the water is analyzed with the Finite Element Method. From the result of the FE analysis nodal velocities on the radiation surface is calculated and used with the boundary conditions of the transducers mounted on the array drum. Then the acoustic pressure is calculated in the field points using the Boundary Element Method and the other acoustic informations, the source level, beam pattern, near field and far-field distance, were acquired.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1127-1133
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• 2003

In this paper, we proposed a novel folded multi-strip monopole antenna whose height is reduced using folded strip structure. It has a broadband characteristic and its measured impedance bandwidth ratio is approximately 1.85 : 1, from 4.55 GHz to 8.4 GHz, for VSWR$\leq$2. Proposed antenna has vertically polarized omni-directional conical beam radiation pattern. It maintains about the same radiation pattern over entire bandwidth.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.105-106
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• 2007

A slot antenna with bazooka balun is designed and implemented for PCS repeater. The proposed antenna improved the return loss and radiation pattern of the slot antenna as combining with the bazooka balun. The antenna was designed by using 3D simulations program, MWS (Microwave Studio). The test result of the slot antenna shows that the return loss is under -10 [dB] for all frequency bands of interests in PCS and maximum gain is about 5.59 [dBi]. And the antenna also shows omni-directional radiation pattern.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.60-65
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• 2015

In the present study, compact $0^{th}$ order resonant antenna for 2.4 GHz ISM frequency band is newly proposed. In case of wireless communication systems such as wi-fi, bluetooth and Zigbee, antennas with omni-directional radiation pattern are necessary because of the demands for uniformly received electric field strength without variation for direction. It is well-known that $0^{th}$ order resonant antennas are not only advantageous for miniaturization but also have advantage of maintaining omni-directional radiation pattern. The proposed antenna is composed of two-element array in which the size of unit element should be smaller than ${\lambda}/4$ correspondent to the resonant length of typical monopole antennas The proposed antenna which is placed at middle and upper side of PCB with $50{\times}50mm^2$ size is designed and fabricated within limited space of $8{\times}5mm^2$. The measured impedance bandwidth ($S_{11}{\leq}-10dB$) is about 100 MHz (2.4~2.5 GHz) which corresponds to quite wide bandwidth in comparison with the antenna size, and also the measured peak gain over the passband is more than 3 dBi which is thought to be slightly wider than the other $0^{th}$ order resonant antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1416-1426
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• 2008

In this paper, we present a small size and multiband directional dipole antenna for mobile communication repeaters. In the omni-directional dipole antenna, a planar reflector under the dipole provides improved directivity in front-direction with wide beamwidth. In order to miniaturize the directive dipole, the size of the reflector is reduced. A vertical stub on the reflector is proposed to enhance the front-directivity of the radiation pattern and mitigate the backward radiation due to the reduced reflector. Furthermore, we use horizontal stubs on edge of vertical stub to obtain additional reduction of the antenna size. To meet the current demand of wireless communication service, the designed antenna shows wideband characteristic by employing electromagnetic coupled two-dipoles with dual-resonance frequencies.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.103-109
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• 1999

In this paper, we proposed to a new structure of T-shaped fed microstrip slot antenna using 2-layers dielectric material with a directional radiation characteristic. When the slot antenna of bi-directional radiation want to radiate only one direction, the reflector must be set up, but this antenna does'nt need set up reflector. T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was also found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. We also analyzed this antenna by using the FDTD method, and calculating waves and electric field distribution in the time domain. we also are calculated return loss, VSWR, and radiation pattern in the frequency domain by Fourier transforming the time domain results, respectively. From the measured results, bandwidth was 34.8% in the center frequency. These results were in relatively good accordance with the calculated values.