• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.349-353
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• 2008

In this paper, the EM wave absorber was designed and fabricated for preventing Reader Interference of RFID communication system in UHF band We fabricated several samples in different composition ratios of Amorphous and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Amorphous and CPE was searched as 80 : 20 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has a thickness of 4 mm and absorption ability was over 20 dB in frequency range of $860\;MHz{\sim}960\;MHz$. Therefore, it was confirmed that the developed absorber can be used for suppressing RFID reader interference in UHF band.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.413-423
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• 2014

With the increasing demands on high data rate, there has been growing interests in multi-input multi-output (MIMO) technology based on spatial multiplexing (SM) since it can transmit independent information in each spatial stream. Recent standards such as 3GPP LTE-advanced and IEEE 802.11ac support up to eight spatial streams, and massive MIMO and mm-wave systems that are expected to be included in beyond 4G systems are considering employment of tens to hundreds of antennas. Since the complexity of the optimum maximum likelihood based detection method increases exponentially with the number of antennas, low-complexity SM MIMO detection becomes more critical as the number of antenna increases. In this paper, we first review the results on the detection schemes for SM MIMO systems. In addition, massive MIMO reception schemes based on simple linear filtering which does not require exponential increment of complexity will be explained, followed by brief description on receiver design for future high dimensional SM MIMO systems.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.243-248
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• 2003

This paper is contents on that construct ultra high speed wireless communication cell backbone net of city using of wireless communication transceiver for millimeter wave band. A new type of 60GHz wave band wireless transceiver using NRD waveguide. This 60GHz transceiver has excellent signal's absorption characteristics of oxygen molecule than the other millimeter wave bands. We constructed service networks to cell interval within about 500m to 3Km laying stress on wireless backbone node using 60GHz transceivers, and did it so that city type wireless communication cell backbone networks of 155.52Mbps ATM(OC-3) may be possible. The possible use of wireless backbone networks technology in a rainy day and a clear day was evaluated at 1Km data link distance. We can measured bit error rate(BER). BER is $10^{-11}$ at 155.52Mbps ATM(OC-3) in a clear day and $10^{-6}$ in a heavy rain more than 35mm per time. Also, we constructed wireless cell backbone networks distance to use several 60GHz transceivers and investigated data transmission rate between main center and local center of long distance. In proposed wireless cell backbone networks, the data throughput was approximately 80Mbit/sec. Therefore, if use transceiver, it is possible that city type ultra high speed wireless communication cell backbone networks construction of 100Mbps, 155.52Mbps, 622Mbps, 1Gbps and 1.2Gbps degrees.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.4
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• pp.426-432
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• 2012

A fully-integrated low power K-band radar transceiver in 130 nm CMOS process is presented. It consists of a low-noise amplifier (LNA), a down-conversion mixer, a power amplifier (PA), and a frequency synthesizer with injection locked buffer for driving mixer and PA. The receiver front-end provides a conversion gain of 19 dB. The LNA achieves a power gain of 15 dB and noise figure of 5.4 dB, and the PA has an output power of 9 dBm. The phase noise of VCO is -90 dBc/Hz at 1-MHz offset. The total dc power dissipation of the transceiver is 142 mW and the size of the chip is only $1.2{\times}1.4mm^2$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.51-57
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• 2016

This paper describes the physical layer modem structure of Giga KOREA 5G system which is being developed by ETRI as a 5G telecommunications prototype. The objective of Giga KOREA 5G system is supporting maximum 100 Gbps data rate for each cell with wide-bandwidth baseband station and mobile station prototypes in mmWave (10~40 GHz) environment. To achieve this objective, its physical layer is composed of high performance baseband station as well as mobile station and their OFDM TDD modems. The important features of Giga KOREA 5G physical layer are carrier aggregation, multiple receiving beam searching in mobile station, high data rate channel encoder and decoder and high speed modulation and demodulation functions.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.22-29
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• 2013

The combined structure of both an annular dielectric resonator and a quarter-wave monopole is proposed to generate an omnidirectional radiation pattern over the wideband frequency range. The monopole works at the lower frequency band and excites the cylindrical dielectric resonator along its center point by electrical coupling mechanism. The rectangular shape of the DR is cut to generate the wideband operation of 4.7-18.2 GHz. The geometrical parameter of cylindrical dielectric resonator is 5.8 mm, 11.6 mm and 6.0 mm in inner diameter, outer diameter and height, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.15-21
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• 2016

In this paper, we considered a design method of a compact quasi-Yagi antenna for portable UHF RFID readers. The antenna consists of a dipole driver and a reflector printed on a dielectric substrate, and it is fed by a microstrip line. In order to reduce the antenna size, the dipole and reflector are bent and the balun between the feeding microstrip line and coplanar strip (CPS) line is integrated within the CPS line. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in UHF RFID band (902-928 MHz). The size of the fabricated antenna is $70mm{\times}75mm$, and the experiment results reveal a frequency band of 892-942 MHz for a voltage standing wave ratio < 2, a gain > 3.5 dBi, and a front-to-back ratio > 6.6 dB over the frequency band for UHF RFID.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.1-7
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• 2017

In this paper, a design method for a compact stepped open slot antenna for an operation in the UWB band is studied. The proposed antenna is miniaturized by inserting L-shaped slots on the ground plane of the stepped open slot antenna through the creation of a resonance in the low frequency, and a strip director is appended to the antenna in order to increase the gain in the middle and high frequency regions. The effects of varying the length of the L-shaped slots, the distance between the director and the slot antenna, and the director length on input reflection coefficient and realized gain characteristics of the proposed antenna are analyzed. The optimized antenna with the size of $30mm{\times}30mm$ is fabricated on an FR4 substrate, and the experiment results show that the antenna has a frequency band of 3.02-11.04 GHz for a VSWR < 2, which assures the operation in the UWB band.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.263-270
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• 2016

This paper implemented an ultra-wideband(: UWB) antenna by using a modified barrel-shaped patch antenna. The designed UWB patch antenna was optimized to match UWB technical specifications by considering the sizes of barrel circle and oval(notch) which is distance between the patch and contact surface and designed antenna was implemented by $10mm(R1){\times}21.8mm$ size. Optimal values on the basis of simulated reflective loss results, the surface current distribution of designed patch antenna was analyzed in order to check operation mode of antenna and wideband mechanism. Experimental results of implemented UWB antenna, Return loss of UWB antenna the voltage standing wave ratio was 2 or less in the 1.775-13.075 GHz band, VSWR in 2 or less. And the maximum gain of approx. 1-3 dBi was found in 3.1-10.6 GHz. This result satisfied the characteristics of ultra-wideband and the proposed antenna will be applicable to an ultra-wideband system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1855-1861
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• 2017

In this paper, the gain enhancement of an SDPA using a director and two parasitic patches is studied. The modified balun is used to increase the bandwidth, whereas the director and two parasitic patches are appended to the SDPA to enhance the gain in the middle and high frequency bands. The effects of the distance between the director and parasitic patches on the antenna performance are analyzed, and the SDPA with a gain over 7 dBi at 1.54-2.99 GHz band is designed. The proposed SDPA is fabricated on an FR4 substrate with a dimension of $90mm(L){\times}135mm(W)$ in order to validate its performance. The fabricated antenna shows a frequency band of 1.56-3.10 GHz for a VSWR < 2, and it is confirmed by measurement that gain maintains over 7 dBi in the frequency range of 1.54-3.00 GHz.