• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.215-218
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• 2009

In this paper, Dual-band bandpass filter studied design using Parallel Coupled SIR(Stepped Impedance Resonator). This Dual-band bandpass filter design SIR of half-wavelength by Parallel-coupled type that is available to RFID system and Changed structure in Meander form by size reduce. Because seen Dual-band bandpass filter is designed so that is applicable for frequency 433MHz and 2.45GHz of RFID system is very wide distance between two pass-band, establish 433MHz by fundamental frequency and controlled 2.45GHz by 2st spurious resonance frequency bandstop filter of 1st spurious resonance frequency and Parallel coupled SIR Combine to remove 1st spurious resonance frequency.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.135-140
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• 2008

In this paper, the spiral antenna with the center frequencies of 315MHz, 433MHz, and 447MHz for RKE system of a vehicle is designed on PCB. The antenna is microstrip line-fed, and applied PIFA concept near the feeding part to easily tune center frequency and input impedance. The PIFA-type spiral antenna with the size of $30mm{\times}20mm$ is designed on printed PCB by considering the effect of circuits and components on PCB, ECU case and vehicle body. Also chip inductor inserted dual-band spiral antenna of 315MHz and 447MHz is designed. We found that the antenna designed on PCB satisfied the antenna specifications through measurement and field test.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.264-265
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• 2007

In this paper, we deal with a hybrid dual band low noise amplifier with tunable matching circuits for a Radio Frequency Identification(RFID) reader operating at 433MHz and 912MHz. The tunable matching circuit consists of the microstrip line, SMD component and varactor. Simulation results show that the S21 parameter is 17dB and 7.91dB at 433MHz and 912MHz, respectively. The noise figure is also determined to 3.56dB and 5.58dB at the same frequencies with a power consumption of 19.36mW.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.746-752
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• 2009

In this paper, we deal with the development of an optimal design program for a triple-band PTFA(Planar Inverted-F Antenna) of 433 MHz, 912 MHz and 2.45 GHz by using evolution strategy. Generally, the resonance frequency of the PIFA is determined by the width and length of a U-type slot used. However the resonance frequencies of the multiple U slots are varied by the mutual effect of the slots. Thus the optimal width and length of U-type slots are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The resonance frequencies of the triple-band PIFA yielded by the optimal design program are 430 MHz, 910.5 MHz and 2.458 GHz that show a good agreement to the design target values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.869-876
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• 2001

In modern wireless communication, it has been regarded as a important problem for the spectrum efficiency to utilize the limited frequency-resource efficiently. In addition, the system architecture has been designed for low cost, low power consumption and ultra-lightweight. In this paper, we directly modulated the BCPFSK with a superior spectrum efficiency using the DDS and applied the direct conversion to the system architecture. Finally, we designed a transceiver which has the 433 MHz BCPFSK output and evaluated the system performance. In the measured result, we know that as for spectrum and the power efficiency, BCPFSK method is better than conventional one. Also, the results of the designed system is 433.92 MHz in center frequency and about 33 dBc in carrier suppression ratio. And we get the better results in local oscillator leakage and the spurious of the ISM out-band the same as -69dBc and under 60dBc.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.159-160
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• 2010

In this paper, we compared the absorption abilities of AMP and Sendust EM wave absorbers for a port logistics RFID system. Firstly, we fabricated EM wave absorber samples by using each absorbing material, AMP or Sendust, and CPE (Chlorinated Polyethylene) with composition ratios 85 : 15 wt. %. Secondly, we designed the optimum EM wave absorber using the calculated material constants found from the measured input impedance of the samples. Therefore, we confirmed that imaginary factor of complex relative permeability influences absorption ability and that AMP is better absorbing material than Sendust at the frequency band of 433 MHz.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1603_1604
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• 2009

본 논문에서는 SIR(Stepped Impedance Resonator)를 이용하여 RFID 주파수 대역의 이중대역 필터를 설계 연구하였다. 반파장 SIR을 parallel-coupled 형태로 설계하고 넓은 주파수 간격의 이중대역필터를 구현하기 위해서 2st 공진 주파수를 2.45GHz 대역에 맞추고 1st 공진 주파수를 억제하기 위해서 대역저지 필터를 결합하였다. 입출력에 대역 저지 필터를 구성하고 반파장 parallel-coulpled SIR은 미앤더 구조로 설계하여 크기를 줄였다. 본 논문에서 설계된 필터는 두 대역에서 -3.5~3.9dB의 삽입 손실을 가지며 433MHz에서 8MHz, 2.45GHz에서 21MHz의 대역폭을 나타낸다. 관심 주파수 이외의 대역에서는 -50dB 이상의 저지 특성을 가진다.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.156-158
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• 2006

A super-regenerative receiver is designed and tested at 433 MHz ISM band, The designed receiver has the data rate of up to 200 kbps and a power consumption of 10 mW. We carried out the system performance test for the TX power of 0.1 mW and 1 m distance. The result of the bit-error rate test shows one bit error among the 4000 bits.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1272-1282
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• 2009

This paper consists of two parts: the protocol for tag-to-tag mesh network and the implementation of dual-radio RFID system. Recently, RFID has been adopted in ports or warehouse, being attached to containers and palettes for loading/unloading automation. However, the RFID system has encountered one problem - some tags cannot receive any command from reader intermittently due to signal interference by containers or field equipments (e. g. cranes and yard tractors). This area where reader signal cannot reach is called dead-zone. The proposed method for solving the dead-zone problem is as follows. A zone which can be communicated directly between readers and tags communicates in 433MHz frequency band in compliance with ISO/IEC 18000-7 standard. On the other hand, dead-zone communicates in 2.4GHz frequency band by using tag-to-tag mesh network in compliance with IEEE 802.15.4 standard. The proposed method can not only save much cost to install additional readers but also help resolve the dead-zone problem. Furthermore, it can provide the easier, faster, and more economical network infrastructure.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.217-227
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• 2010

To apply active RFID technology in the various kinds of industry, it needs to quickly transmit a large amount of data. ISO/IEC 18000-7 standard uses the 433.92MHz as single channel system and its transmit rate is just 27.8kbps, that is insufficient for a large amount of data transmission. To solve this problem, we designed a new data transmission protocol using 2.4GHz band. The feature of designed protocol is not only making over 255bytes data messages using the Burst Read UDB but also efficiently transmitting it. To implement this protocol, we use Texas Instruments's SmartRF04 develop kit and CC2500 transceiver as RF module. As an evaluation of 63.75kbytes data transmission, we demonstrate that transmission time of Burst Read UDB has improved as 17.95% faster than that of Read UDB in the ISO/IEC 18000-7.