• The Journal of the Acoustical Society of Korea
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• v.18 no.4
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• pp.11-16
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• 1999

In this paper, we designed and fabricated QMSA(Quarter-Wavelength Microstrip Antenna) for 850MHz band on the CGP-500 PTFE substrate(by CHUKOH company) with ε/sub r/=2.6, H=1.6mm(±0.08), where width of the radiation patch is .identical with that of the ground plane. A well matched feed point was obtained by experiments and this QMSA was fed by using prove feed method. The resonant frequencies and the return losses were mcasured by cutting the gap L₃ between the radiation patch and the ground plane, with a 5mm cutting length, step by step. As a result, we found that the measured return losses were decreased and the resonant frequencies were increased when the gap L₃ was shorter, especially under 10mm, unlike we had expected.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.679-687
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• 2017

In this paper, a microstrip-fed triple-band monopole antenna with DGS (Defected Ground Structure) for WLAN/WiMAX applications was proposed. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get triple band characteristics. We carried out simulation about parameters. Adjusted the position and length of the two strips and three slits, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate of which the dielectric constant is 4.4, and its overall size is $34mm(W_1){\times}34mm(L_1){\times}1.6mm(t)$, and its proposed antenna size is $17.0mm(W_6){\times}30.75mm(L_3+L_4+L_9)$. From the fabricated and measured results, return loss of the proposed antenna satisfied return loss -10dB bandwidth 360 MHz (2.335~2.695 GHz), 645 MHz (3.37~4.015 GHz) and 1,770 MHz (5.14~6.91 GHz). And measured results of gain and radiation patterns characteristics displayed for operating bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.562-569
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• 2001

This paper presents the optimum design method for T-shaped microstrip-line-fed slot antennas on various substrates. Since the impedance bandwidth of the antenna depends highly on the vertical offset position and the length of horizontal strip conductor, we derived the formulas regarding these design parameters to get the maximum bandwidth. The formulas can compute the offset position and the length of horizontal strip conductor for any given substrate parameters. We compared the results obtained by using these design formulas and the one obtained by the simulation for each slot width, and it showed very good agreement.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.3
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• pp.40-44
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• 1983

A wide band quasi-log periodic microstrip antenna is designed using circular-disc microstrip patches as a basic radiator. The radiating elements are series-fed by a coplanar feeding network which consists of an open circuited feed line with a branch line connected to each radiating element. Experiment results show that the values of VSWR are less than 2.3 over the range of 2.72-3.43 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.260-269
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• 2005

In this paper, we propose a microstrip line fed printed monopole antenna which has an ultra-wideband characteristic. Proposed antenna can improve the bandwidth characteristic with the taper structure formed by modified ground plane and radiating element. Measured impedance bandwidth ratio of the antenna is more than 30:1; from the lower frequency of 0.89 GHz to the upper frequency of more than 30 GHz for VSRW$\leq$2. The antenna has conical radiation pattern that has low radiation gain to $\theta$=0$^{\circ}$ direction and higher radiation gains as $\theta$ increases.

• Journal of electromagnetic engineering and science
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• v.17 no.1
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• pp.44-49
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• 2017

A compact planar microstrip-fed ultra-wideband (UWB) antenna with a dual band-notched for UWB application is presented and analyzed. By inserting a U-shaped slot and inverted U-shaped slot into the pot-shaped radiator, two notched bands are achieved. By optimizing the width and length of the U-shaped slots and inverted U-shaped slot, a desired bandwidth of voltage standing wave ratio (VSWR) less than 2.0 can be achieved, ranging from UWB bands with notched dual bands. The proposed antenna is fabricated on an inexpensive FR-4 substrate with overall dimensions of $28.0mm{\times}39.5mm$. The measured results confirm that the proposed antenna covers from 1.775 to over 13.075 GHz with two rejection bands of around 3.325-3.925 GHz and 5.3125-6.025 GHz. In addition, the proposed antenna showed good radiation characteristics and gains in the UWB bands.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.376-380
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• 2014

In the present study, oblique L-shaped monopole slot antenna with broadband characteristic is newly proposed. For bandwidth enhancement as well as size reduction, L-shaped slot with two open-terminations on the ground edge is used. The lower part of L-shaped slot comprises oblique form for bandwidth enhancement in low frequency band, whereas its higher part comprise tapered form for its enhancement in high frequency band. The short-circuit terminated microstrip line which is generally known to be more useful for bandwidth enhancement than open-circuit termination is used. The measured impedance bandwidth($S_{11}{\leq}-10dB$) and gain of the fabricated antenna have been observed to be 4.72 GHz (2.28~7 GHz) and more than 3dBi over the passband respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.610-618
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• 2000

A T-shaped microstripline -fed printed slot antenna is anlayzed by using the transmission line model(TLM) in this paper. Microstrip-slotline junction is modeled by employing a transformer and the transformer turn ratio is derived empirically. The method is extended to the case of $1\times2,l\times4$array antennas. Return loss results obtained by using the transmission line model. The maximum measured results and demonstrated the usefulness of the transmission line model. The maximum bandwidths of a single antenna, $1\times2,l\times4$ array antennas are 28.5%, 47.8%, and 50.9%, respectively, for the VSWR$\leq2$. The gain of $1\times4$ array antenna is 7.97dBi and the beamwidth is about $27^{\circ}$.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.2-11
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• 2001

The L-shaped strip is shown to be an attractive feed for the thick mierostrip antenna (thickness around 10% of the operating wavelength). The L-strip incorporated with the radiating patch introduces a capacitance suppressing some of the inductance introduced by the strip itself. In this paper, a wideband microstrip patch antenna fed by L-strip for the PCS ($1,750{\sim}1,850MHz$) and IMT-2000 ($1,920{\sim}2,170MHz$) broad-band is presented. A two-element array fed by L-strip is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth is over 31% (VSWR < 1.5, 615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.63-64
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• 2013

In this paper, a design method for a dual dipole antenna for an operation in the frequency band of 470-806 MHz for indoor digital TV (DTV) is studied. The proposed antenna is composed of two planar dipoles connected by parallel strip line, and the antenna is fed by a microstrip line. By employing different lengths of dipoles, a broadband characteristics is obtained, and the antenna is size-reduced by bending both ends of the longer dipole. The effects of each parameters on the antenna performance are examined by simulation, and the parameters are optimized for the DTV use. A prototype antenna with optimized parameters for the indoor DTV use is fabricated on an FR4 substrate and tested experimentally. The experimental results show that the frequency band for a VSWR < 2 ranges 458-864 MHz (61.4%, bandwidth 406 MHz, 1.89:1), and it corresponds fairly well with the simulated band 448-868 MHz (63.8%, bandwidth 420 MHz, 1.94:1).