• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.187-192
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• 2017

We investigated the effects of the CSRR-metamaterial on microstrip comb-line array antennas. Microstrip comb-line array antennas was designed with 12 radiators, gain of 16.09dBi and bandwidth of 0.24GHz in the 24GHz ISM band. The designed antenna had radiation beam perpendicular to the antenna plane, co-polarization gain of 16.09dBi and cross-polarization gain of -10.86dBi. the CSRR-metamaterial increased largely the impedance bandwidth of the antenna from 0.24GHz to 3.6GHz. however as co-polarization gain became 10.08dBi and cross-polarization gain became 14.1dBi, co-polarization was mixed with cross-polarization. And the antenna gain lowered by 1.99dB. On the investigation of the dependence on the split-direction of the CSRR rings, it showed nearly the same characteristics for up-splitted ring used case and down-splitted ring used case. However in the case of arranging up-splitted ring and down-splitted ring in alternation, co-polarization gain decreased to -1.29dBi and cross-polarization gain increased to 13.9dBi, which meant the wave was transited to cross-polarization majority wave.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.195-201
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• 2014

In this paper, an AccessPoint compact microstrip patch antenna was designed by using L-shaped feeding structure of a Fractal Structure and the compact antenna can be obtained by the rare formed presence of the resonance flow which is called "Crossed-Diagonal". CST's MicroWave5.0 was used for the design. As the operating characteristics of the patch antenna, it showed the characteristic of 1031 [MHz] or 29.4% in the range of 3.202 [GHz] ~ 4.233 [GHz] when an input return loss is less -10 [dB] and VSWR 2:1, also as it is in this paper, we got simulation results such as, gains of the E-plane and H-plane are 8.7 [dBi] and 8.6 [dBi] for this is the single patch, and 3 [dB] beamwidth is $43.9^{\circ}$ at E-plane and $78.7^{\circ}$ at H-plane.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.1-8
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• 2011

In this paper, data transmission corrugated horn antenna for RF sensor satellite system and its radiation characteristic are presented. The proposed antenna is designed, fabricated and measured to obtain the maximum gain at ${\pm}60^{\circ}$ of its radiation patterns. The result of the proposed antenna is that the return loss is less than -15 dB and the gain is over 5 dBi at ${\pm}60^{\circ}$ of its radiation patterns. From these results, it is confirmed that the proposed can be used as data transmission corrugated horn antenna for RF sensor satellite system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.55-61
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• 2013

In this paper, we describe design and implementation of audio encoder/decoder for voice synthesis. It uses the encoding of difference value of successive samples instead of the original sample value. and has the compression ratio of 4. The function is verified by using FPGA and the performance is measured by the fabricated chip using $0.35{\mu}m$ standard CMOS process. The system clock is 16.384MHz. The measured THD+n is from -40dB to -80dB with frequency variation and the power consumption is about 80mW. It is suited for the mobile application of high audio quality and low power consumption.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.116-122
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• 2009

Mobile Wireless Sensor Network is an organized collection of sensor nodes and mobile sink nodes, in which the sensor node transmits the signal to the sink node. In real environment, there are many cases in which sinks have mobility caused by the people, the vehicle and etc. Since all nodes in the sensor networks have limited energy, many researches have been done in order to prolong the lifetime of the entire network. In this paper we propose Dynamic Local Update-based Routing Protocol(D-LURP) that prolong the lifetime of the entire network to efficiently maintain frequent location update of mobile sink static sensor nodes in Mobile WSNs. When the sink node moves out of the local broadcasting area the proposed D-LURP configures dynamically the local update area consisted of the new local broadcasting area and the previous dissemination node(DN) and find the path between the DN and the sink node, instead of processing a new discovering path like LURP. In this way the processing of broadcasting sink node's location information in the entire network will be omitted. and thus less energy will be consumpted. We compare the performances of the proposed scheme and existing Protocols.

• Broadcasting and Media Magazine
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• v.15 no.1
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• pp.58-66
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• 2010

• Broadcasting and Media Magazine
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• v.15 no.2
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• pp.44-52
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• 2010

• ETRI Journal
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• v.41 no.1
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• pp.7-9
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• 2019

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.231-237
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• 2016

This paper presents a multiband low phase noise CMOS VCO with wide frequency tunability using switched bondwire inductor bank. The combination of bondwire inductor and CMOS switch transistor enhances frequency tunability and improves phase noise characteristics. The proposed multiband VCO operates from 2.3GHz to 6.3GHz with phase noise of -136dBc/Hz and -122dBc/Hz at 1 MHz offset frequency, respectively. Switched bondwire inductor bank shows high quality factor(Q) at each frequency band, which allows better tradeoff between phase noise and power consumption. The proposed VCO is designed in TSMC 0.18um CMOS process and consumes 7.2 mW power resulting in figure of merit(FOM) of -189.3dBc/Hz at 1 MHz offset from 6GHz carrier frequency.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.43-46
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• 2018

This paper has designed a wideband bandpass filter (WBSF : Wide Band Stop Filter) using a stepped impedance resonator (SIR : Stepped Impedance Resonator) with improved performance and improved hairpin coupling structure. The SIR WBSF is small in size and has the advantage of having excellent bandstop characteristics. The designed BSF has a structure in which a quadrangular shaped hairpin of a / 4 length is arranged symmetrically on the upper and lower sides of the input and output transmission lines. The input and output terminals were terminated at 50 ohms for system applications. The center frequency of the SIR WBSF is 6.3 GHz, which is the second harmonic of 3.15 GHz. The designed filter has a 3dB bandwidth of 2.9 GHz and a transmission coefficient ($S_{21}$) of 33.2 dB. The reflection coefficient ($S_{11}$) at the center frequency is 0.106 dB. The application field is used for fixed microwave relay stations, fixed satellite and earth stations, and fixed satellite communications. The overall size is $20mm{\times}10mm$.