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

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

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.5
• /
• pp.845-852
• /
• 2024

In this paper, we propose mult-band antenna included Sub-6 GHz band for WLAN system. The proposed antenna has the fourth strip line and slot in the partial ground plane to obtain impedance matching. The total substrate size is 48.0 mm (W)×50.0 mm (L), thickness (h) 1.0 mm, and the dielectric constant is 4.4, which is made of 26.0 mm (W2)×42.0 mm (L1+L2+4.0(L1+L2+4.0 mm+L8+L9) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 115 MHz (0.825 to 0.940 GHz) for 900 MHz band, 210.0 MHz (2.29 to 2.50 GHz) for 2.4 GHz band, 270.0 MHz (3.45 to 3.72 GHz) for 3.5 GHz band, and 930.0 MHz (4.95 to 5.88 GHz) for 5.0 GHz band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency triple band as required.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.11 s.353
• /
• pp.175-184
• /
• 2006

In this paper, we describe a 900MHz CMOS RF transceiver using an ISM band for ZigBee applications. The architecture of the designed rx front-end, which consists of a low noise amplifier, a down-mixer, a programmable gain amplifier and a band pass filter. And the tx front-end, which consists of a band pass filter, a programmable gain amplifier, an up-mixer and a drive amplifier. A low-if topology is adapted for transceiver architecture, and the total current consumption is reduced by using a low power topology. Entire transceiver is verified by means of post-layout simulation and is implemented in 0.18um RF CMOS technology. The fabricated chip demonstrate the measured results of -92dBm minimum rx input level and 0dBm maximum tx output level. Entire power consumption is 32mW(@1.8VDD). Die area is $2.3mm{\times}2.5mm$ including ESD protection diode pads.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.2
• /
• pp.345-354
• /
• 2024

In this paper, we propose a triple band WLAN antenna for Wi-Fi 6E band with DGS. The proposed antenna has the characteristics required frequency band and bandwidth by considering the interconnection of two strip lines and three areas on the ground place. The total substrate size is 31 mm (W) × 50 mm (L), thickness (h) 1.6 mm, and the dielectric constant is 4.4, which is made of 22 mm (W₆ + W₄ + W₅) × 43mm (L₁ + L₂ + L₃ + L₅) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 340 MHz (1.465 to 1.805 GHz) for 900 MHz band, 480 MHz (2.155 to 2.635 GHz) for 2.4 GHz band and 1950 MHz (4.975 to 6.925 GHz) for 5.0/6.0 GHz band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency triple band as required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.9
• /
• pp.899-903
• /
• 2003

In this paper, a wide band helical antenna for mobile handset using parasitic element effect has been investigated. To obtain the effect of parasitic element, we utilized the cylindrical conductor which is not feed. As thickness of cylindrical conductor is increasing, second and third resonance frequency become abruptly variable. In case of that 4.5mm diameter parasitic element cylindrical conductor is inserted, normal mode helical antenna obtained bandwidth of around 900 MHz on the limit of R. L., - 5 dB.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.96-100
• /
• 2001

본 논문에서는 skeleton slot 복사기를 이용하여 GSM 900과 GSM 1800에서 사용할 수 있는 이중대역 안테나를 설계 및 제작하여 측정 결과를 비교 분서하였다. 기본적인 skeleton slot 구조에서는 낮은 밴드의 2배 이상의 주파수에서는 수평 빔폭이 일정치 않고, 정재파비 특성이 불량하였으나, 급전부와 측면 방사부분의 다중경로 형성 및 절곡 구조를 이용하여 이를 해결하였다. 안테나의 크기는 반사판이 190$\times$190(mm), 복사기는 154$\times$106(mm), 높이는 33mm로 하여 현재 서비스 사업자틀이 주로 사용하는 크기로 구성하였다. 구성 재질은 1mm 두께의 알류미늄판을 이용하며, 이를 NCT로 타공 및 절곡하여 제작하였기 때문에 대량 생산 시 단가를 낮출수 있다. 실측결과 900MHz 대역에서 13.7%, 1800MHz 대역에서 16.4%의 -l0dB 반사손실 대역폭을 만족하고, 방사패턴도 대역별로 $\pm$1$^{\circ}$이내의 일정한 양상을 보여 이중대역 안테나로서의 요구를 만족하였다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.10
• /
• pp.841-851
• /
• 2013

Mobile RFID/NFC linkage technology means a provision of integrated 2 existing mobile RFID services by developing the 900MHz mobile RFID reader and the NFC reader/tag into one SoC to be put on a USIM card. In this paper, the mobile RFID related technologies that offer similar services as NFC were also analyzed to understand the potential linkage to NFC and the requirements for the linkage. In addition, the introduction of dual tag and the code system linkage suggested a linking method to maximally use the existing infrastructure and the requirement satisfaction was analyzed. Lastly, based on the analysis, the future direction for the new standard design was suggested.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.9A
• /
• pp.2141-2152
• /
• 1998

In this paper, we design and implement an indoor wireless modem using small signal of ISM band regulation, which can tranceive reliable data streams. We use direct sequence spead spectrum (DS-SS) signaling with synchronous BPSK and QPSK modulation, convolutional coding with viterbi decoding. The radio frequency module uses frequency devision duplexing in 900 MHz band, and the digital module is implemented with FPGAs for the purpose fo ASIC design. The perfomrance of our own acquistion and tracking circuit consisting digital matched filter and decision logic is proved by experiments, and the possibility of file transfer at indoor environment with the entrie system that the modem is connected the PC through RS-232C port is verified.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.12
• /
• pp.7-12
• /
• 2008

In this paper, a highly efficiency power amplifier is presented for multi-band antenna system. The class F power amplifier operating in dual-band designed with one LDMOSFET. An operating frequency of power amplifier is 900 MHz and 2.14 GHz respectively Matching networks and harmonic control circuits of amplifier are designed by using the unit cell of composite right/left-handed(CRLH) transmission line(TL) realized with lumped elements. The CRLH TL can lead to metamaterial transmission line with the dual-band holing capability. The dual-band operation of the CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. Because the control of all harmonic components for high efficiency is very difficult, we have controled only the second- and third-harmonics to obtain the high efficiency with the CRLH TL. Also, the proposed power amplifier has been realized by using the harmonic control circuit for not only the output matching network, but also the input matching network for better efficiency.