• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.312-318
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• 2006

WRC-2000 allowed HAPS to provide IMT-2000 service in the bands 1885-1980 MHz, 2010-2025 MHz and 2110-2170 MHz which have been utilized by the conventional terrestrial IMT-2000 service. In this paper, we analyze the interference effects from HAPS into terrestrial IMT-2000 system in adjacent band. To do this, in this paper, we have analyzed the interference and the sharing criteria between HAPS and the conventional terrestrial/satellite mobile system by considering the service and system requirements, the specification of system and developing the interference scenarios and the analysis algorithms.

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.232-237
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• 2020

In this paper, a compact microstrip-fed dual-band planar antenna for global positioning system (GPS) and mobile handset applications is presented. Dual operating frequency bands are achieved by an open end L-shaped slot and a bent rectangular slot. The proposed antenna is designed and fabricated on the FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm and size of 57 × 57 ㎟. The measured impedance bandwidth (|S₁₁|≤ -10dB) of the fabricated antenna is 60 MHz(1550 ~ 1610 MHz) in the GPS band and 670 MHz (1690 ~ 2360 MHz) in the DCS / IMT-2000 band, covering the required bandwidths for GPS(1570 ~ 1580 MHz) and DCS / IMT-2000 (1710 ~ 2200 MHz) bands. In particular, it has been observed that antenna has a good omnidirectional radiation patterns as well as high gain of 2.36 dBi and its efficiency is more than 90 % over the entire frequency band of interest.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.7
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• pp.24-30
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• 2000

In this paper, we proposed an fiber-optic transceivers based on the analog optical transmission techniques of incorporating the SCM (subcarrier multiplexing) and WDM (wavelength-division multiplexing ) method, which can be used to transmission of IMT-2000 and PCS wireless frequency band and analyzed overall those parameters related with fabrication. Especially in the impedance matching network between RF signal and LD, we proposed the method of deriving optimal performance using simulation techniques. In the frequency band of 1.7GHz∼2.25GHz, experimental data for the gain flatness and the noise floor of the optical link were also presented $\pm$1.5dB and -130dBm respectively when the link Rain was 0dB.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.197-200
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• 2004

In this paper, a novel triple-band planar inverted F antenna(PIFA) is proposed. The goal of this paper is to design a small antenna which is operated in triple band. Using T-shape slit and stacked U-shape parasitic patch, good impedance matching is achieved in three band. T-shape slit is inserted on the main patch in order to effectively control the excited patch surface current distributions. The proposed antenna occupies a small volume of $26{\times}9.5{\times}6mm^3$, and the obtained impedance bandwidths cover the required operating bandwidths of the GPS(1565-1585MHz), IMT-2000(1885-2200MHz) and Bluetooth (2400-2484MHz) bands.

• ETRI Journal
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• v.29 no.4
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• pp.536-538
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• 2007

We propose and describe the fabrication of a linear power amplifier (LPA) using a new analog feedforward method for the IMT-2000 frequency band (2,110-2,170 MHz). The proposed analog feedforward circuit, which operates without a pilot tone or a microprocessor, is a small and simple structure. When the output power of the fabricated LPA is about 44 dBm for a two-tone input signal in the IMT-2000 frequency band, the magnitude of the intermodulation signals is below -60 dBc and the power efficiency is about 7%. In comparison to the fabricated main amplifier, the magnitude of the third intermodulation signal decreases over 24 dB in the IMT-2000 frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.996-1005
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• 2000

This paper proposed a novel broadband ceramic dielectric antenna by improving the conventional broadband technique that very high permittivity material is attaching to one side of low permittivity material. The broadband ceramic dielectric antenna can be designed by using our proposed method, and it overcomes the disadvantage of narrow bandwidth problem. For the proposed ceramic dielectric antenna, a 10 dB return-loss bandwidth of 33.9% has been achieved. The measurement and numerical results(Finite Element Method) are performed and confirmed to a good agreement with each other. The proposed ceramic dielectric antenna is designed and implemented to extend enough the coverage of dual band (PCS+IMT-2000).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.676-679
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• 2001

A low-temperature cofired-ceramic (LTCC) multi-layer ceramic (MLC) band-pass filter (BPF) is presented, which has the benefits of low cost and small size. The BPF is designed for a IMT-2000 handset. The computer-aided design technology is also presented. The BPF with an attenuation pole at below the passband has been discussed and realized. The equivalent circuit of the BPF was established by transmission lines and lumped capacitors. The frequency characteristics of the LTCC-MLC BPF is well acceptable for IMT-2000 application.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.397-400
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• 2001

In this paper, to improve bandwidth of microstrip antenna, we discussed the patch structure using Aperture Stacked Patch. To provid PCS service and IMT-2000 service simultaneous, a microstrip patch antenna needs impedance bandwidth of 22%. But typical microstrip patch antennas have impedance bandwidth of 3∼6%. To analyze characteristics of microstrip pach antenna, we used Ensemble of commercial software. The microsrtip patch antenna was designed and fabricated, tuned. We get following results; 650MHz(33%) of impedance bandwidth for VSWR 1.5. The measured gain of ASP microstrip antenna is 6.94dBi.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.56-60
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• 2002

A low-temperature cofired-ceramic (LTCC) multi-layer ceramic (MLC) band-pass filter (BPF) is presented, which has the benefits of low cost and small size. The BPF is designed for an IMT-2000 handset. The computer-aided design technology is also presented. The BPF with an attenuation pole at below the passband has been discussed and realized. The equivalent circuit of the BPF was established by transmission lines and lumped capacitors. The frequency characteristics of the LTCC-MLC BPF is well acceptable for IMT-2000 application.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.156-161
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• 2006

In this paper, GPS/IMT2000/Wireless LAN compact chip antenna is designed for mobile communication system. The proposed antenna size is $10.2mm{\times}21mm{\times}1mm$. It consists of three meander lines. dual resonance frequencies is achieved by two effective current paths using two meander lines and via. also The parasitic meander line structure is added. The coupling is adjusted by arranging parasitic meander line for triple-band. The fabricated antenna achieve triple-band. The resonance frequencies are 1.672GHz, 2.092GHz, 2.504GHz. The impedance bandwidths of each resonance frequencies are 156MHz, 272MHz, 64MHz. The maximum radiation gains of fabricated antenna are 0.08dBi, 1.67dBi, -1.44dBi. The proposed antenna achieve quasi monopole radiation pattern.