• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.3
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• pp.136-147
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• 2009

In this paper we analyze the influence of source/drain (S/D) extension region design for minimizing short channel effects (SCEs) in 25 nm gate length single and double gate Silicon-on-Insulator (SOI) and Germanium-on-Insulator (GOI) MOSFETs. A design methodology, by evaluatingm the ratio of the effective channel length to the natural length for the different devices (single or double gate FETs) and technology (SOI or GOI), is proposed to minimize short channel effects (SCEs). The optimization of non-overlapped gate-source/drain i.e. underlap channel architecture is extremely useful to limit the degradation in SCEs caused by the high permittivity channel materials like Germanium as compared to that exhibited in Silicon based devices. Subthreshold slope and Drain Induced Barrier Lowering results show that steeper S/D gradients along with wider spacer regions are needed to suppress SCEs in GOI single/double gate devices as compared to Silicon based MOSFETs. A design criterion is developed to evaluate the minimum spacer width associated with underlap channel design to limit SCEs in SOI/GOI MOSFETs.

• Composites Research
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• v.17 no.5
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• pp.68-77
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• 2004

The electromagnetic (EM) absorption or shielding characteristics of a material is an important issue not only for military purpose but also for commercial purposes such as radar, electric or telecommunication devices. In order to design the effective electromagnetic wave absorber, the electromagnetic characteristics of the constituents of the material should be available in target frequency band. Also, it must be possible to predict the electromagnetic properties of absorbers with respect to the content of lossy ingredients. In this study, the dielectric properties of unsaturated polyester resins containing nano-size conductive carbon black powder were measured with a free space method in the X-band frequency range and analyzed with respect to the content of carbon black. Finally, the method for estimating the dielectric properties of polymeric resin containing conductive carbon black with respect to the EM frequency was developed and verified.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.153-157
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• 2008

The MCS(Micro-coplanar strip) line has been analyzed. The conformal mapping method is used to calculate the quasi-static effective permittivity and characteristic impedance of this MCS line. The computed results of the present work are found to be in good agreement when compared with the results obtained using commercial S/W, IE3D. And in this paper, the stepped-impedance low pass microstrip filter is designed and fabricated with MCS lines for improving the frequency responses. The LPF proposed structure has been also designed and implemented to have the sharp attenuation characteristics in stop band. The agreement between simulation and measurement results verify the implemented LPF.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.363-370
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• 2019

The recent development of information and communication technologies brings new changes to automobile traffic systems. The most typical example is the advancement of dedicated short range communication(DSRC). DSRC mainly consists of an intelligent transportation system(ITS), an electronic toll collection system(ETCS) and an advanced traveler information system(ATIS). These wireless communications often cause unnecessary electromagnetic waves, and these electromagnetic waves, in turn, cause frequent system malfunction. To solve this problem, an absorber of electromagnetic waves is suggested. In this research, various materials, such as powdered metal and iron oxides, are used to test the possibility for an effective absorption of the unnecessary electromagnetic waves. The various metal powders are made into a thin sheet form by compositing through processing. The electromagnetic characteristics(complex permittivity, complex permeability) of the fabricated sheet are measured. As a result, we achieve -6.5 dB at 940 MHz(77.6 % absorption rate) with a 1.0 mm-thickness electromagnet wave absorber, and -9.5 dB at 940 MHz(88.8 % absorption rate) with a 2.0 mm-thickness absorber.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.70-75
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• 2017

In this paper, we studied the RF characteristics of a voltage-controlled artificial transmission line employing periodically arrayed diodes for application to highly miniaturized wireless communication systems on an MMIC (monolithic microwave integrated circuit). According to the results, the novel voltage-controlled artificial transmission line employing periodically arrayed diodes exhibited a short wave length, which was only 35.2% that of the conventional transmission line, owing to increasing capacitance. In addition, it's effective permittivity and effective propagation constant exhibited considerably higher values than those of the conventional transmission line. Furthermore, attenuation constant of the voltage-controlled artificial transmission line was far higher than that of the conventional transmission line. Using the closed-form equation, we theoretically analyzed the equivalent circuit of the voltage-controlled artificial transmission line.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.297-297
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• 2007

The $(B_{0.5},Sr_{0.5})TiO_3$ ceramics, which added with low sintering materials $Li_2CO_3$ and ZnBO, was investigated for LTCC(low temperature co-fired ceramic) applications. To compare sintering temperature of $(B_{0.5},Sr_{0.5})TiO_3$ respectively, we added 1, 2, 3, 4, and 5wt% of $Li_2CO_3$ and ZnBO to $(B_{0.5},Sr_{0.5})TiO_3$. For confirming the sintering temperature, the respective specimens were sintered from $750^{\circ}C$ to $1200^{\circ}C$ by $50^{\circ}C$. The case of $Li_2CO_3$ greatly lowered the sintering temperature of $(B_{0.5},Sr_{0.5})TiO_3$ ($1350^{\circ}C$) below $900^{\circ}C$. The addition of ZnBO improved the loss tangent of $(B_{0.5},Sr_{0.5})TiO_3$. The crystalline structure of $LiCO_3$ doped $(B_{0.5},Sr_{0.5})TiO_3$ and ZnBO doped $(B_{0.5},Sr_{0.5})TiO_3$ was analyzed with the X-ray diffraction (XRD) analysis. The dielectric permittivity and loss tangent of $Li_2CO_3$ doped BST and ZnBO doped BST were measured with the HP 4284A precision. From the electrical characterization, we respectively obtained the dielectric permittivity 1361, loss tangent $6.94{\times}10^{-3}$ at $Li_2CO_3$ doped $(B_{0.5},Sr_{0.5})TiO_3$ (3wt%) and the dielectric constant 1180, loss tangent $3.70{\times}10^{-3}$ at ZnBO doped $(B_{0.5},Sr_{0.5})TiO_3$(5wt%).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.796-808
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• 2007

In this paper, two novel compact microstrip bandstop filters using complimentary split ring resonators(CSRRs) and spiral resonators is proposed. The first one is the bandstop filter using an array of CSRRs etched on the center line of a microstrip. The bandstop is due to the presence of negative effective permittivity and positive permeability near resonant frequency which prevent the wave propagation. The second on is the bandstop filter using an array of spiral resonators etched on the center line of a microstrip. The bandstop is due to the self-resonance of spiral circuit. We have achieved controllable resonance frequency and bandwidth, super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff. The electrical sizes of two proposed filter are very small. Additionally, they can be easily fabricated and compatible with MMIC or PCB technology.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.1
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• pp.37-46
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• 2003

The transient responses on arbitrarily interconnected digital transmission lines are analyzed by an efficient node discretization technique. Since the proposed node discretization technique offers an efficient means to discretize transmission lines, the transient waveform at any position on the arbitrarily interconnected lines is easily predicted. Dispersive microstrip multiconductor transmission lines arbitrarily connected are analized for generality. The derivation of frequency-dependent equivalent circuit elements of coupled transmission lines have been carried out by the spectral domain approach(SDA). The effects of variations of excited pulse width on the crosstalks of the high-speed microstrip coupled-lines are also investigated. It has been well known that the crosstalk spike level is monotonously increased when the coupling length and effective permittivity of substrate are increased. In this paper, it is found that the variations of crosstalk level are not further monotonous as shortening the exciting pulse width toward several picosecond. The results are verified by the generalized S-parameter technique.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.10-15
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• 2015

A thin-film transmission line (TFTL) employing a microstrip line/coplanar waveguide (ML/CPW) was fabricated on a silicon substrate for application to a miniaturized on-chip RF component, and the RF characteristics of the device with the proposed structure were investigated. The TFTL employing a ML/CPW composite structure exhibited a shorter wavelength than that of a conventional coplanar waveguide and that of a thin-film microstrip line. When the TFTL with the proposed structure was fabricated to have a length of ${\lambda}/8$, it showed a loss of less than 1.12 dB at up to 30 GHz. The improvement in the periodic capacitance of the TFTL caused for the propagation constant, ${\beta}$, and the effective permittivity, ${\varepsilon}_{eff}$, to have values higher than those of a device with only a conventional coplanar waveguide and a thin film microstrip line. The TFTL with the proposed structure showed a ${\beta}$ of 0.53~2.96 rad/mm and an ${\varepsilon}_{eff}$ of 22.3~25.3 when operating from 5 to 30 GHz. A highly miniaturized impedance transformer was fabricated on a silicon substrate using the proposed TFTL for application to a low-impedance transformation for broadband. The size of the impedance transformer was 0.01 mm2, which is only 1.04% of the size of a transformer fabricated using a conventional coplanar waveguide on a silicon substrate. The impedance transformer showed excellent RF performance for broadband.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.52-57
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• 2015

In this paper, we studies on the RF characteristics of the transmission line employing IPACD (inverted periodically arrayed capacitive devices) on MMIC (monolithic microwave integrated circuit) for application to wireless communication system. According to measured results, the novel transmission line employing IPACD showed a wavelength much shorter than conventional transmission lines. In addition, the IPACD structure showed an effective permittivity much higher than conventional ones. We also extracted the bandwidth characteristic of the IPACD structure using equivalent circuit analysis. According to the results, the cut-off frequency of the proposed structure was 129.2 GHz.