• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.9-18
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• 2006

This paper presents a Monte-Carlo based method to obtain a probability of interference in the 900MHz passive RFID systems. We show an efficient algorithm to calculate not only in-band interference due to unwanted emission of interfering sources for a given emission mask, but out-of-band interference, which depends on the blocking performances of a victim receiver filter. We next apply the proposed method to two types of RFID systems, one is to use simple FHSS and the other to adopt a hybrid use of FHSS and LBT, which senses the channel before transmission. Simulation is first performed with a SEAMCAT. We next make simulation with a MATLAB software which implements SEAMCAT algorithm and show both results from two softwares are similar.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.290-293
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• 2007

RFID 시스템은 주파수마다 다른 인식 거리를 가지며, 장거리 시스템의 900MHz의 경우 1m에서 최대 10m까지 인식 범위를 가진다. 주파수는 거리에 의하여 해당 파장이 감쇠하는 현상이 생하며, PSK 질문기에서 발생하는 전파는 1/4파장 변화에 의하여 출력 신호 극성이 반전되며 허용 인식범위 내 응답기에서도 적합한 통신이 안되는 영역이 발생하였다. 본 연구에서는 900MHz RFID 장비를 기본으로 안테나와 태그의 위치를 변경하여 테스트를 진행하여 어떤 지정에서 음영구역이 발생하는지 테스트를 진행하고, 문제점이 발생하는 원인에 대하여 논하며 이런 문제점을 해결하기 위하여 일본에서 2.4GHz RFID 응답기에서 사용하는 베이스 밴드 FSK 변조회로를 기반한 900MHz RFID 응답기 설계방안을 제안한다.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.141-142
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• 2006

본 논문에서는 단일 FET를 이용하여 900MHz/2.14GHz 이중 대역 고효율 도허티 전력증폭기 설계 구현을 하였다. 이중대역 도허티 전격증폭기의 출력전력은 900MHz 에서 35.91dBm, 2.14GHz에서 35.91 dBm의 출력을 얻었으며, 전력부가효율은 900MHz에서 40.32%, 2.14GHz에서는 40.47%의 효율을 획득 하였다. 또한 본 논문에서 단 하나의 능등소자를 이용하여 최대한의 출력전력을 얻기 위하여 최대 전력정합법을 사용하였으며 그 결과 이중대역 전력증폭기를 구현할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.997-1000
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• 2006

In this paper, we have used the 900Mha RF band and produced the transmitter-receivers to measure the distance of moving range of a crane. We selected the analog signal of 450Khz middle frequency band of the RF Baseset module, and the property data of phase response is analysed to estimate the range distance. We have earned the good results from the experiment.

• Journal of information and communication convergence engineering
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• v.9 no.1
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• pp.16-20
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• 2011

In this paper, we designed and implemented an internal multi-band folded monopole antenna for mobile handset. The proposed antenna covers Global System for Mobile Communications (GSM900: 880~960 MHz), Digital Communications System (DCS: 1710~1880 MHz), US-Personal Communications Service (US-PCS: 1850~1990 MHz), Bluetooth(2400~2484 MHz), WiMAX(3400~3600 MHz), and Wireless Local Area Network (WLAN: 5150~5350 MHz, 5725~5875 MHz) band for Voltage Standing Wave Ratio $(VSWR)\;{\le}\; 3$. The measured peak gains of the implemented antenna are -1.78dBi at 920MHz, 2.72dBi at 1795MHz, 2.25dBi at 1920MHz, 2.34dBi at 2442MHz, 2.11 dBi at 3550MHz, and 2.04 dBi at 5250MHz.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.1-7
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• 1999

A single RF transceiver evaluation board have been developed for the purpose of application to the 900MHz band transceiver contained RF-IC chip And environment test was evaluated. The RF-IC chipset includes LNA(Low Noise Amplifier), down-conversion mixer, AGC(Automatic Gain Controller), switched capacitor filter and down sampling mixer. The RF evaluation board for the testing of chipset contained various external matching circuits, filters such as RF/IF SAW(Surface Acoustic Wave) filter and duplexer and power supply circuits. With the range of 2.7~3.3V the operated chip revealed moderate power consumption of 42mA. The chip was well operated at the receiving frequency of 925~960MHz. Measurement result is similar to general RF receiving specification of the 900MHz digital mobile phone.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.288-297
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• 2007

The novel internal monopole chip antenna of penta-band operation for GSM850/GSM900/DCS/USPCS/WCDMA bands for mobile phones is proposed. This antenna occupies a small volume $8\times3.2\times20mm^3$ and is suitable to be embedded in a mobile phone as an internal antenna. The minimization of the proposed antenna was realized by using spiral line structure and meander line structure on FR-4 of dielectric$(\varepsilon_r=4.4)$. The designed antenna has the wide-band operation in the upper band by overlapping high order resonances. The measured bandwidth of this antenna (VSWR>3) is 150MHz$(1,030\sim1,180\;MHz)$ in the lower band operation and 650 MHz$(1,760\sim2,410\;MHz)$ in higher band operation. The measured radiation efficiency within bandwidth(VSWR 3:1) is over 50 %. The antenna has been designed by a commercial software HFSS.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.58-65
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• 2013

It's introduced a BLA(Branch Loop Antenna) that is modified from conventional loop, and verified antenna performances for applying to mobile handset. Branch elements are added to a rectangular loop, and low resonance is obtained by the length of the branch line. When resonance frequency of a single loop is 2.5GHz, BLA had near 900 MHz under the same antenna size. Multiple resonances are established by the locations of branch connection and their lengths. By the implementation and measurement for the dual band BLA, it's showed 75MHz -10dB bandwidth and -3.03~-1.46dBi average gains with 49.73~71.39% efficiencies at GSM900 band, and 90MHz -6dB bandwidth and -8.14~-2.17dBi average gains with 15.34~60.62% efficiencies at DCS1900 band. And H-plane radiation patterns were omni-directional. These performances are good for the mobile handset antenna.

• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.54-61
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• 2009

In this paper, Switching to digital TV broadcasting and mobile operators license expiration period of the frequency, time and 700MHz, 800MHz and 900MHz frequency band plan for the redistribution is actively being discussed. Redistribution policy direction of these frequency 800MHz (bandwidth 10MHz) integrated command frequency for wireless networks(i.e TETRA) is expected to be considered a redistribution. These Integrated Wireless Network Infrastructure configurations at the time and data communication capabilities of the system unwilling TETRA Release 2 standard for the system is presented. This system is analyzed that Release 1 of the existing system takes up more than 6 times the increase of frequency bands. Therefore, integration of the frequency band assigned to the command of a wireless network with the introduction of advanced systems will not be able to do. In this paper to the digital TV transition, and the policy based on analysis of trends in the 700MHz band for the integration of wireless networks, provides policy direction for the allocation plan.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.2
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• pp.9-17
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• 2011

In this paper, a bike management system using 900 MHz RFID technology has been developed. There are limits to the 13.56 MHz spectrum of existing management systems, which are single tag identification and the short possible identifying distance of the technology. In this paper, we use 900 MHz instead of 13.56 MHz in order to make wide recognition and multi-tag identification possible. Granted, there are also many benefits to using 13.56 MHz RFID tags, which include compatibility with existing bike management systems. This system was developed on the 900 MHz band using RFID similarly to existing 13.56 MHz systems in order to be able to manage multiple bikes at the same time.