• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.900-905
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• 2006

In this paper, PIFA antenna for $2.40{\sim}2.482GHz\;and\;5.75{\sim}5.85GHz$ is designed, fabricated, and measured. The prototype consist of hair-pin and short-pin. To obtain suitable bandwidth, the form layer is inserted between ground plane and substrate. Important parameters in the design are hair-pin length, width, position, air-gap height, and feed point position. From these parameters optimized, a PIFA antenna is fabricated and measured. The measured results of the antenna are obtained as follows results. The resonant frequency of the fabrication PIFA antenna is 2.37GHz and 5.86GHz bandwidth for approximately 90MHz with 350MHz(VSWR<2.0) and the gain is $1.91{\sim}4.37dBi$. H-plan and E-plan at 2.4GHz and 5.8GHz are shown as $52.83^{\circ},\;85.90^{\circ}\;and\;68.68^{\circ},\;52.143^{\circ}$ respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.42-52
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• 2012

In this paper, a waveguide antenna is designed and fabricated for side and rear radar sensor of vehicles in UWB (Ultra Wide Band) high band (center frequency : 9.5 GHz, -10 dB bandwidth : 600 MHz (6.4 %)). For the radar antenna, a probe fed rectangular waveguide antenna having simple structure and wide bandwidth is used. An important performance factor in this antenna is the isolation between transmitting (TX) and receiving (RX) waveguide antennas because this radar system uses TX and RX antennas separately. Thus the isolation between two antennas was simulated for E-plane and H-plane array. As a result, it was verified that the isolation of the H-plane array of the antennas is better than E-plane array, due to the TE10 mode. Therefore, H-plane arrayed waveguide antennas were mounted on a T-shaped radar module and performance of antennas was investigated. The -10 dB bandwidth of the TX and RX antenna mounted on T-shaped radar module was measured as 1000 MHz (10.52 %) and 1090 MHz (11.47 %) respectively and the isolation is less than -50 dB in the operation band. The peak gain is 7.65 dBi for the TX antenna and 7.26 dBi for the RX antenna and the beamwidth of H-plane of TX and RX antenna was measured as $64^{\circ}$ and $65^{\circ}$ respectively. Consequently, we verified that the proposed waveguide antenna is appropriate for a vehicle radar applications.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.4
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• pp.25-33
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• 1999

Leaky wave radiation and surface wave launching problems in a dielectrically covered and periodically slitted parallel-plate waveguide(PPW) are considered for the TEM wave incidence case. Both the infinite and finite periodic geometries are analyzed by use of the method of moments. Some numerical results for the reflected and transmitted powers in the PPW, radiation efficiency into the free space, surface wave launching efficiency into the slab, antenna gain, and radiation patterns against dielectric thickness are presented to show the effect of the dielectric cover on the performances of the slitted leaky wave antenna. In addition, the method for improving surface wave launching efficiency using the proposed periodic geometry is described and maximum launching efficiency of 97.5% is obtained theoretically. So this structure is thought to be promising as an efficient feeder of dielectric grating antenna as well as image guide.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.280-288
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• 2009

In this paper, a high-power and low-loss stripline 10-way power divider is designed and fabricated fur the feed network of an S-band linear array antenna with Chebyshev current distribution which has a narrow beam width and low side lobe level(SLL) of 35 dB or more. The unit cell of the power divider is based on a T-junction power divider and the whole divider is comprised of the cascaded unit cells. The multi-stage impedance transformer and modified ring hybrid are used in designing the power divider for performance improvement. And the reflection loss and insertion loss are improved by modifying a connector structure for a coaxial-to-stripline transition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.151-153
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• 2010

In this paper, the tri-band planar monopole microstrip antenna which stimulaneously meets the three bands such as TRS, WLAN and DMB is designed. The designed antenna size was smaller using CPW-fed structure that shows a ground-plane and a patch-plane are existed at one layer. The proposed antenna is designed on FR-4 substrate with a relative dielectric constant 4.3, thickness of 1.5mm and tangent loss 0.04. The designed antenna shows that VSWR is below 2 and has good return loss below -10dB over the three bandwidths.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.932-940
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• 2005

In this paper, a planar half-circle shape ultra-wideband(UWB) antenna fed by CPW is designed, fabricated and measured for UWB communications. Within the UWB band(3.1 GHz${\~}$10.6 GHz), 5.15 GHz${\~}$5.825 GHz frequency band is used by IEEE 802.1la WLAN applications. It may be necessary to notch out this band to avoid interference with IEEE 802.1la WLAN. Therefore, we have proposed three kinds of UWB antennas having a notch function, such as a rectangular slot, a hat-shaped slot a circle-shaped slot. The notch frequency of the proposed antenna can be adjusted by controlling the slot length or slot width. From the measured results, the proposed antennas show a good gain flatness except the IEEE 802.1la WLAN frequency band and have a reasonable agreement with simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.416-422
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• 2006

In this paper, we have designed and favricated the high gain and wideband microstrip patch antenna including IEEE 802.11a. To widen the bandwidth of microstrip antenna, firstly we have used the microstrip line-coaxial probe feeding method and inserted a U-slot in the rectangular patch. Secondly, to improve the antenna gain, we have used a $2{\times}2$ array structure. From the measured results, wideband characteristics of 1 GHz bandwidth($5.110{\sim}6.142$ GHz) for VSWR<2 was obtained. The measured eain was 13 dBi in both the E-plane and H-plane at the frequency of 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.85 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.528-537
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• 2011

In this paper, a broadband antenna of the CPW structure with a band-notched characteristic is presented. To obtain this characteristic, the complementary split ring resonator(CSRR) is inserted in the ground plane. In addition, the IEEE 802.11a WLAN band(5.15～5.825 GHz) appears in the band-notched characteristic. The proposed antenna dimension is $36{\times}60{\times}1.6\;mm^3$, and it is designed on the FR-4 substrate having a relative dielectric constant of 4.4. The designed antenna shows that the resonant frequency is 2.03～10.78 GHz below the return loss of -10 dB and a VSWR less than 2 was satisfied. As a result, the proposed CSRR has a band-notched characteristic in the range of 4.917～6.017 GHz which the center frequency is about 5.4 GHz band.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.223-228
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• 2021

In this paper, we proposed a slot-type antenna with microstrip feed embedded in a PCB for Zigbee communication (2.4 ~ 2.484 GHz). The proposed antenna is designed on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 50×65 mm². Through simulations, trends of design parameters are analyzed and optimized, and the proposed antenna composed with three slots satisfy the frequency band. The measured impedance bandwidths (|S₁₁| ≤ -10 dB) of fabricated antenna are 900 MHz (2 ~ 2.9 GHz) in Zigbee frequency band. In addition, the radiation pattern showed omnidirectional characteristics for E and H-planes, and the gain of antenna in Zigbee frequency band was 1.782 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.42-49
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• 2018

In this paper, a dual-band microstrip-fed monopole antenna with a DGS(defected ground structure) for WLAN(wireless local area network) applications is presented. The antenna consists of a monopole and a defected ground, which were etched on both sides of the FR-4 substrate. The defected ground structure was used to obtain the dual band, while the step-by-step reduction in the monopole width was used to improve the impedance matching of the antenna. The antenna has an overall compact size of $44{\times}51{\times}1.6mm^3$, which was optimized by varying the size of the monopole and the ground plane such that it may resonate at the 2.4 GHz and 5 GHz bands of the WLAN. The measurement results showed that the antenna operates in the frequency band of 210 MHz(2.29~2.50 GHz) and 900 MHz(5.05~5.95 GHz) for a VSWR under 2, and showed omnidirectional radiation pattern at all desired frequencies.