• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1287-1292
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• 2012

In this paper, a dual polarization patch antenna operates at the wide bandwidth of 1.525GHz~1.665GHz was designed and fabricated. To obtain the wide bandwidth and high gain, increased height of air floor from GND was applied, and to get wide band axial ratio and high gain, parasitic patch was applied. The simulation and measurement showed good agreements, the VSWR was less than 1.9 at the frequency bandwidth, the return loss was less than -10dB, and the LHCP(Left Hand Circular Polarization) and RHCP(Right Hand Circular Polarization) isolation was less than -13dB at the frequency bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.2
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• pp.83-91
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• 1987

In this paper, the extended inverse Chebyshev function have been derived from Chebyshev function. We presented normalized biquads coefficients of n=5, 6 for passband attenuation Ap(dB)=0.1, 0.2, 0.5, 1.0, 2.0, 3.0 and stopband frequency Ws(rad/s)=1.2, 1.3, 1.4, 1.5, 1.6. A designed low-pass filter from extended inverse Chebyshev transfer function produces the magnitude haracteristic which is maximally flat in the passband and equalripple in the stopband as shown in fig. 3(c), (d). Finally, it showed the magnitude and loss characteristics through realistic circuit simulation, and presented element values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.630-638
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• 2001

This paper has been proposed a structure composed of FIRs and IIR filters as digital decimation filter to compensate the drooping inband on the high precision AU chips. The area of chip has been reduced compared with the conventional structure because the RAM and MAC is reduced. The passband ripple$(\leq\; 0.4535 \times fs)$, passband attenuation(at $\; 0.4535 \times fs$ and stopband attenuation$(\geq\; 0.59\times fs)$ of the 6th-order $\Delta\Sigma$ modulator and digital decimation filter had $\pm0.0007[dB]$, -0.0013[dB] and -110[dB] respectively. Also the inband group delay, which was almost same compared with the conventional digital decimation filter structure, was 30.07/fs[s] band the error of group delay was 0.1672%.

• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.441-446
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• 2003

Earlier efforts on optical access concentrated on the design of PONs for the collection and distribution portion of the access network. The PON architecture is very simple but it requires a MAC protocol for control of upstream traffic. The MAC protocol must support QoS (Quality of Service) administration function by various traffic class, efficient dynamic bandwidth assignment function, CDV (Ceil Delay Variation) minimization function etc. This paper proposes a dynamic bandwidth assignment algorithm of the MAC protocol for a broadband access network using an Ethernet Passive Optical Network supporting various traffic class. We compare our proposed with MDRR algorithm using simulation, and confirmed that our proposed Request-Counter algorithm produces shorter average cell delay.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.59-63
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• 2007

In this paper, we propose an advanced Ka-band satellite HD broadcasting system using scalable video coding technology. As already known, it is not so easy to achieve reasonable link availability on Ka-band because of the rain-attenuation effect, and in case of HD broadcasting service it's more difficult. To overcome that problem, we propose an hierarchical broadcasting system based on H.264 SVC technology. In this paper, we suggest a few types of system scenario to realize the concept. Those scenarios are including DVB-S and DVB-S2 and spatially scalable video stream is the source stream in all cases.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.495-496
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• 2008

본 논문에서는 UHF 대역 RFID 의 국제표준인 ISO/IEC 18000-6C 표준을 만족하는 태그 칩을 위한 저전력 고성능 아날로그 회로를 설계하였다. 설계된 아날로그 회로는 성능 테스트를 위해 메모리 블록을 포함하고 있으며, 태그의 인식률과 경제성을 위해 저 전력 및 칩 면적의 최소화에 중점을 두고 설계하였다. 설계된 UHF 대역 RFID 태그용 아날로그 회로는 0.24Vpeak의 RF 입력으로 동작이 가능하며, 칩 면적은 $552.5{\mu}m{\times}338.8{\mu}m$, UHF 대역 RFID 태그 칩에 적합한 작은 면적을 갖는다.

• Journal of Digital Contents Society
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• v.5 no.3
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• pp.187-191
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• 2004

Rapid time variations of the mobile communication channel have a dramatic effect on the performance of multi-carrier modulation. This paper analyzed the bit error rate (BER) performance for multi-carrier code division multiple access (MC-CDMA) network, and derived the equivalent signal-to-total noise plus interference(SNIR) of MC-CDMA system in the reverse link, the performance of MC-CDMA/BPSK signal is evaluated taking into account the fraction of partial-band interference and interference power. and the effect of partial-band interference is comprehensively studied in order to further improve the Qos of multi-carrier multimedia system.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.10
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• pp.12-21
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• 1998

A chaotic spread spectrum communication system using a polar quarternary method is designed and implemented. Four different chaotic signals in the relation of multiplication each other are generated through the use of a coupled synchronization method in the transmitter which is composed of four Chua's circuits. Information is retrieved at the receiver which is connected to the transmitter through the use of a drive synchronization method. Since spread spectrum of information signal is spread by chaotic signal, the configuration of the system is simpler than that of any other conventional system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.171-174
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• 2011

In this paper, transformed IFA design is proposed to improve the antenna gain of GSM/DCS/PCS band. New antenna structure has been approved to be more convenient matching in the mobile phone terminal and increase gains and expansion bandwidth through the simulation and real measurement. According to measurement, it's shown 1.57dB higher average gain than conventional IFA.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.71-75
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• 2008

A folded monopole antenna is proposed for mobile communication applications. The proposed antenna covers CDMA and GSM at low frequency band, and it has a wide bandwidth (6.85 GHz) at high frequency band to cover GPS, DCS, USPCS, UHfS, WLAN (2.4, 5.2, 5.8 GHz), and the future application of IEEE 802.16e mobile WiMAX.