• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.17-27
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• 2016

In the high-frequency characterizations of planar circuit components, measurement data may not be physical. It is mainly due to resonance effects concerned with discontinuities which are inevitable for a planar component characterization. In this paper, a novel accurate transmission line characterization method is presented that excludes the resonance effects based on measurement data reconfirmation. For the physically obvious data acquisition near the resonance frequencies of a transmission line, the additional lines with different line lengths are fabricated on the same substrate. The test transmission lines are characterized by using vector network analyzer (VNA) in 100 MHz to 26.5 GHz. It is shown that an accurate transmission line characterization can be achieved with the proposed measurement data reconfirmation technique.

• Journal of electromagnetic engineering and science
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• v.18 no.1
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• pp.1-6
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• 2018

In this study, the analytic expression for the positive/negative $n^{th}-Mode$ resonance frequency of an N unit cell composite right-/lefthanded (CRLH) transmission line is derived. To explain the resonance mechanism of the $n^{th}$ mode, especially for the negative mode, the current distribution of the N unit cell CRLH transmission line is investigated with a circuit simulation. Results show that both positive and negative $n^{th}$ resonance modes have n times current variations, but their phase difference is $180^{\circ}$ as expected. Moreover, the positive $n^{th}$ resonance occurs at a high frequency, whereas the negative $n^{th}$ resonance transpires at a low frequency, thus indicating that the negative resonance mode can be utilized for a small resonator. The correlation between the slope of the dispersion curve and the bandwidth is also observed. In sum, the balanced condition of the CRLH transmission line provides a broader bandwidth than the unbalanced condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1094-1102
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• 2010

In this paper, the problem of electromagnetic transmission via slits in a cavity inside conducting screen of finite thickness is considered for the case that the TE(to the slit axis) polarized plane wave is incident on the slit in conducting screen. Using the method of moments the variations of the transmitted power through the slits are obtained and compared with those computed from an equivalent circuit constructed using an equivalent slit admittance. It is found that the effective slit width of a narrow slit, at resonance, becomes $1/{\pi}$ wavelengths independently of the actual slit width. The transmission resonance phenomena in the proposed geometry are explained in connection with the variations of an equivalent admittance of the slit in the cavity.

• Journal of electromagnetic engineering and science
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• v.15 no.2
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• pp.104-110
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• 2015

As civil infrastructures continue to deteriorate, the demand for structural health monitoring (SHM) has increased. Despite its outstanding capability for damage identification, many conventional SHM techniques are restricted to huge structures because of their wired system for data and power transmission. Although wireless data transmission using radio-frequency techniques has emerged vis-$\grave{a}$-vis wireless sensors in SHM, the power supply issue is still unsolved. Normal batteries cannot support civil infrastructure for no longer than a few decades. In this study, we develop a magnetic resonance-based wireless power transmission system, and its performance is validated in three different mediums: air, unreinforced concrete, and reinforced concrete. The effect of concrete and steel rebars is analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.569-575
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• 2007

The transmission resonance phenomenon through a narrow slit in the thick conducting screen is analyzed by use of the method of moments. In order to check the validity of this approach, some numerical results for the transmission coefficient is compared with previous ones. In particular, an approximate expression for the transmission width is derived in the analytical form.

• Journal of Magnetics
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• v.11 no.2
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• pp.90-94
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• 2006

A finite-element method is used to analyze loss generation and electromagnetic noise absorption characteristics of a coplanar waveguide transmission line integrated with a magnetic thin film. Parameters used in the analysis are the electrical resistivity of the magnetic layer and the thickness of both magnetic and insulating layers. The results indicate that L-C resonance is the main loss mechanism of the electromagnetic noise absorption.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.83-90
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• 2009

In this paper, the problem of electromagnetic transmission through slits in two parallel conducting plates which separate two half spaces is considered. The coupled integral equations for the electric field distributions over the slits are developed for the case that the TM polarized plane wave is incident on the slit and solved by the method of moments. The transmitted power beyond the slit-perforated conducting parallel plates is computed in order to check the variations of the coupled power through slits against some parameters such as the incident angle of the TM polarized wave, slit width, lateral distance between two slits, and distance between the conducting plates. When the lateral distance between two slits approaches near the multiples of half wavelengths, the transmission resonance (maximum power transmission) is observed. If the slit width in the incident side is narrow and the distance between conducting plates is small compared to the wavelength, the maximum of transmitted power is observed to be nearly independent of the incident angle and slit width. In addition, the mechanism of the transmission resonance in the present geometry is explained using a simplified geometry and its equivalent circuit.

• Journal of electromagnetic engineering and science
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• v.1 no.1
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• pp.37-42
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• 2001

This paper presents the basic characteristics of a cutoff cavity-hacked slot antenna, for the application of spacetenna, with a feed post and a parasitic post inserted parallel to the slot. This type of antenna might effectively excite the slot and forcibly resonate the cavity by adding external reactance to the parasitic post. The Galerkin\`s method of moments is used to analyze integral equations for the unknown electric current on each post and electric field in the slot. The value of external reactance for forced resonance is discussed by deriving a determining equation, the current distribution on each post and the radiation patterns are considered. The analysis is in excellent agreement with the experiment for the radiation patterns.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.349-354
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• 2013

Wireless power transmission introduced by Tesla has instrumented by many scientists of the world. This technique first was utilized as wireless communications such as radio in long range transmission. And contactless transmission using inductive property was used on white goods. In 2007, MIT' lab introduced that new wireless power transmission by magnetic resonance which has about 50% efficiency and 2M transmission distances, it was a chance to refocus a new possibility of wireless power transmission. In this paper, using LC coupling compensate the short distances of contactless transmission, this simple method could transmit about 30cm distances. Using this approach, it can be solved the short transmission distances, a drawback of Electromagnetic inductive coupling method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.832-836
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• 2008

In this study, the electromagnetic coupling problem through narrow slit in an infinite conducting screen is considered for the case that the TM polarized plane wave is incident upon the slit. This study aims at explaining the mechanism of the maximum power transmission via the resonated slit using the equivalent circuit. It is shown that the transmitted power through the slit for the case of resonance corresponds to the power normally incident upon the conducting plane of the effective width 1/pi wavelengths, irrespective of the slit width. Some similarities between the maximum power transmissions observed in both the proposed structure and narrow slit in thick conducting screen are described from the viewpoint of equivalent circuit. In addition, it is found that, when the slit is resonated, the transmitted power equal to the scattered power.