• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.9
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• pp.13-19
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• 1998

It was shown that the bandwidth of T-shaped microstripline fed slot antenna is wider than many of the conventional feeding structures. In this paper, we proposed a new method of enhancing the bandwidth of T-shaped microstripline fed slot antenna with a shunt open stub, and analyzed this antenna by using the FDTD method. We have computed waves and electric field distribution in the time domain, and VSWR, input impedance and radiation pattern in the frequency domaim by Fourier transforming the time domain results. It was found that the bandwidth of this antenna depend on the position(L$_1$) and length(L$_2$) of a shunt open stub. When these parameters are L$_1$=30 mm and L$_2$=33mm, we obtained the maximum bandwidth at the center frequency of 2.3 GHz. From the computed results, the optimum antenna is designed and fabricated. The fractional bandwidth of this antenna was 53.9 %. The measured results were in relatively good accordance with computed values.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.47-54
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• 2005

The design method for a dual frequency antenna using CPW feed lines is presented. The antenna structures can be simplified by CPW feed lines and easily designed on integrated circuits. The presented antenna has two resonant frequency ranges and each respective resonant frequency is determined by its own length of monopole antenna. We used an impedance matching method by using a monopole coupling related to the ground of CPW feed lines As a result, the resonant frequencies were 5.25[GHz] and 23.5[GHz] and their bandwidths $35.2\%,\;and\;41.3\%$, respectively, and also, the separation of the two frequencies $370\;%$. We presented an analytical designing method to implement a dual frequency monopole antenna and showed simple antenna structures having two frequency ranges for RFIC Integrations.

• 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.7 s.98
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• pp.768-775
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• 2005

In this paper, the broadband cross monopole antenna is presented and the radiation characteristics is investigated f3r various width and height of the radiated element. In the presented antenna, the broadband characteristics is realized by the cross monopole element and the impedance matching section between the element and the ground. To conform the broadband characteristics of the presented antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in $1.75\~2.655$ GHz. It is shown that the designed antenna has the nondirectional pattern in the horizontal plane, the directional pattern in the vertical plane, VSSR less than 1.5, and gain in $2.5\~3.78$ dBi. From these results, the presented antenna is conformed as a broadband indoor antenna which can be used for PCS, WCDMA, Wibro, and satellite DMB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.178-183
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• 2006

The proposed triple-band compact chip antenna using coupled meander line and stacked meander structure for mobile RFID/PCS/WiBro. The proposed antenna is designed to operate at 900, 1,800, and 2,350 MHz, and is realized by parasitic coupled and stacked a meander line. Meander lines are using extend length of effective current path more than monopole and contribute miniaturization. The coupled meander line controls the excitations of the mobile RFID and PCS, stacked meander line controls the excitation of the WiBro. The fabricated antenna size is $10.98{\times}22.3{\times}0.98\;mm$. The resonance frequencies are 905 MHz, 1.77 GHz and 2.32 GHz. The impedance bandwidths are 24 MHz, 140 MHz and 92 MHz. The maximum gains of antenna are 0.34 dBi, 2.58 dBi and 0.4 dBi at resonance frequencies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.993-999
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• 2006

This paper presents the design simulation, implementation, and measurement of a miniaturized DCS, PCS / Satellite DMB dual-band stacked chip antenna with double coupled line for mobile communication terminals. A stacked meander is realized by using a via hole with height of 0.8 mm and a diameter of 0.35 mm to connect upper- and lower-layer meander sections for a reduction of the dimensions of the antenna. In addition the stacked meander chip antenna is extended by a double coupled-line to achieve two different radiation modes. A ratio of the first frequency and second frequency vary with the geometrical parameter of coupled lines. The fabricated antenna used FR-4 substrate with relative permittivity of 4.2. And its dimensions are $15.2{\times}7{\times}0.8mm^3$. The measured impedance bandwidth(VSRW<2) are 244 and 120 MHz at the operating frequency, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.781-787
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• 2004

In this paper, a novel dual and wide band aperture stacked patch antenna for Cellular/PCS/IMT-2000 base station is presented. It consists of single microstrip patch having notches along the radiating patch, two dielectric substrates and a form material. To achieve wide band characteristic, we utilize the coupling effect between the notched patch and the resonant aperture in the ground plane and by properly cutting notches on the patch, an aperture stacked patch antenna could be designed to yield dual frequency operation. By the proper choice of resonant aperture size and height of a foam material, dual and wide band characteristic could be realized the measured impedance bandwidth(1:1.5 VSWR) of designed antenna at lower band(860 MHz) reaches 77 MHz and covers the Cellular CDMA band(824∼894 MHz). The measured impedance bandwidth(1:1.5 VSMR) of the designed antenna at upper band(1,960 MHz) is about 550 MHz and covers both the PCS band(1,750∼l,870 MHz) and the for-2000 band(1,920∼2,170 MHz). Good broadside radiation with high gain(5.65∼7.4 dBi) characteristics have also been observed.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.934-941
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• 2014

In this paper, we present a low profile 2-layered meander built-in monopole antenna for portable RFID reader using FDTD(Finite Difference Time Domain) method. The input impedance, return loss, and VSWR in the frequency domain are calculated by Fourier transforming the time domain results. The double meander 2-layer structure is used to enhance the impedance matching and increase the antenna gain. The measured bandwidth of the antenna is 0.895 GHz ~ 0.930 GHz for a S11 of less than -10dB. The measured peak gain of proposed low profile RFID built-in antenna is 2.3 dBi. And the proposed built-in antenna for portable RFID reader can offers relatively wide-bandwidth and high-gain characteristics, in respectively. Experimental data for the return loss and the gain of the antenna are also presented, and they are relatively in good agreement with the FDTD results. This antenna can be also applied to mobile communication field, energy fields, RFID, and home-network operations, broadcasting, and other low profile mobile systems.

• Journal of Advanced Navigation Technology
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• v.12 no.5
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• pp.420-428
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• 2008

In this paper, Stack structure patch antenna has been designed and fabricated for wireless LAN applications. The patch and ground plane were used by PEC metal. It was 0.05 [mm] thick. In order to broaden the bandwidth of the antenna and improve of gain, the stack structured antenna with probe feed. The measured input return loss showed less than -10 [dB] at the broadband from 5100 to 6140 [MHz]. It's measured bandwidth was 1040 MHz. The gain of antenna in the E-plane and H-plane was 13 dBi and 3 dB beam width was $40^{\circ}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.281-290
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• 1999

This paper presents the development of a high power amplifier for a transmitter of INMARSAT-C operating at L-band(1626.5∼1646.5 MHz). To simplify the fabrication process, the whole system is designed of two parts composed of a driving amplifier and a high power amplifier The HP's AT-41486 is used for driving part and the SGS-THOMSON microelectronics' STM1645 is used the high power amplifier. The SSPA(Solid State Power Amplifier) was fabricated by the both circuits of RF and temperature compensation in aluminum housing. The realized SSPA has more than 36 dB for small signal within 20MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output Port are less than 1.5:1, respectively. The output Power of 42.2 dBm is achieved at the 1636.5 MHz. These results reveal a high power amplifier of 20 Watt which is the design target.