• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.6
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• pp.654-660
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• 2011

In this paper, the electromagnetic wave transmission through a ridge-loaded small circular aperture is considered. The transmission problem when a plane wave is normally incident on the aperture in an infinite conducting plane is solved by a method of moments(MoM). From the results for the transmitted power and the patterns of radiation from the aperture, the transmission characteristics of a small sub-wavelength circular aperture, a ridge-loaded circular aperture, and a half wavelength slot are compared. In addition, the theoretical study is verified through the experiments for the apertures fabricated on an Flexible Printed Circuit Board(FPCB), which shows fairly good agreements with the simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1138-1147
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• 1999

In this paper, two types of $2\times2$ Rx/Tx microstrip patch antenna are proposed to implement Ku-band satellite communications. The single-fed dual resonance patch antenna as the first type derives perpendicular polarizations at two resonant frequencies from a single patch radiator, using aperture coupling via a bended single-feeding line and a cross-shaped slot. The double-fed dual resonance patch antenna as the second type implements dual resonance with mutually orthogonal polarizations by mixing the two feeding mechanisms of the microstrip line and the aperture coupling. Especially, in the double-fed dual resonance antenna case, air-gap is introduced to broaden the bandwidth. Through measurement, each of the two types of antenna was verified to function properly both Rx and Tx. The double-fed dual resonance antenna shows excellent performance in the bandwidth and the crosspolarization characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1664-1667
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• 2003

Aperture-coupled microstrip antenna is one type of microstrip antennas. This type of antenna has bandwidth wider than simple microstrip antenna. Herein, we use two substrates, that have the same dielectric constant 2.47 (PTFE-quartz) in which upper substrate is a rectangular patch. The microstrip patch is fed by a microstrip line which is printed on lower substrate, through an aperture or slot in the common ground plane of patch and microstrip feed. This antenna is analyzed by using Finite Difference Time Domain (FDTD) method the specific design frequency 10 GHz and match impedance is 50 ohms. The simulation results of its characteristics are input impedance, return loss, VSWR and radiation patterns respectively.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.75-82
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• 2006

In this paper, we design the meander line inductors with high sensitivity and high quality factor(Q) using high characteristic impedance of aperture ground plate. Sensitivity as a frequency is new defined by variation of effective inductance per analysis frequency range instead of self resonance frequency (SRF). An equivalent lumped circuit is derived to explain the characteristic of high frequency inductor. The 4 nH meander line inductor with aperture ground plate has 0.45 nH/GHz of good sensitivity and 86 of Q at 0.7 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.12
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• pp.1058-1063
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• 2015

In this article, we propose a near field microwave scanning probe structure in which two short conducting rods are attached to the center of the ridged(H-type) aperture, thereby reducing significantly the beam spot area while maintaining the high transmission efficiency through the output coupling H-type(ridged) aperture. Here the two short parallel conducting rods seem to play an important role of concentrating the transmitted electromagnetic energy through the H-type aperture and so reducing the beam area for high resolution. For validation of the proposed theory, the near field waveguide probe is fabricated according to the simulated results and its return loss characteristics versus frequencies are measured. The comparison between theory and experiment is seen to be in good agreements.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1399-1405
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• 2012

Transmission cross section characteristics as a measure of transmission efficiency has been analyzed numerically for the H-shaped and C-shaped small apertures in the infinite conducting plane when illuminated by a plane wave. It has been found that C-shaped aperture has the larger transmission cross section than that of H-shaped aperture under the condition of the same perforated aperture area. Main attention has been focused on studying the mutual coupling effect between two C-shaped apertures on the transmission cross section characteristic. Parallel configuration which is composed of two C-shaped apertures arranged along the x-axis and collinear configuration which is composed of two C-shaped arrayed along the y-axis have been investigated from the viewpoint of enhanced transmission cross section characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.6
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• pp.470-477
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• 2017

As a method of the transmission efficiency improvement of an aperture smaller than the wavelength, we modified the conventional H-shaped resonant aperture to lower the resonance frequency of resonant aperture, and the transmission efficiency of resonant aperture was improved more than the conventional aperture. The maximum transmission cross section(TCS) calculated using the equivalent circuit tends to be almost equal to the maximum TCS from the small resonant aperture modified to improve the transmission efficiency. The transmission characteristics of resonant apertures can be quantified as the TCS, and the transmission efficiency of that can be compared. The modified resonant aperture has a maximum TCS increased by about 2.87 times from $846mm^2$ to $2,431mm^2$ compared to the H-shaped aperture, and the resonant frequency decreased from 5.06 GHz to 2.92 GHz, and the length-to-wavelength ratio of the aperture was reduced from 0.178 to 0.103.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.865-868
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• 2005

A Helmholtz resonator is one of noise control elements widely used in many practical applications. The resonator has very high absorption at resonance frequency but the frequency bandwidth is very small. Therefore many kinds of additional resistive screens have been applied to the resonator's neck in order to increase the bandwidth. This paper discusses the absorptive characteristics of a Helmholtz resonator damped by a flexible porous screen in form of wire mesh. First, various experimental results are introduced and studied. Secondly, the effect of the resistive screen is theoretically predicted. It is shown that the distance between the screen and aperture affects on the resonance frequency as well as the absorption of the system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1454-1459
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• 2010

This paper presents the comparison of electric field penetration in Bell laboratories and IEC 61000-2-9 standard when HEMP source penetrates through an aperture in a planar conducting plane of infinite extent. HEMP electric field distributions assume in order to interpret this problem. Integral equation is derived and solved by Galerkin's method of moments for calculating the penetrating electric field. It is shown that penetrated electric field of IEC 61000-2-9 standard is greater than the Bell Laboratories waveform in resonance of lower frequency band, but those waveforms are similar in shape to frequency domain.