• Journal of electromagnetic engineering and science
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• v.8 no.1
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• pp.28-33
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• 2008

We have proposed a novel DVB-H(Digital Video Broadcast for Handheld) antenna for folder-type mobile handheld terminal by using a coupling element, a stub, and an L-type matching circuit. The L-type matching circuit consisting of two chip inductors is used for achieving an improved impedance matching over the DVB-H frequency band ($470{\sim}702\;MHz$). Simulated results showed the stub worked to more knot the lower and upper frequency ends of the input impedance curve. The antenna exhibits a flat gain characteristic from 2 to 2.8 dBi over the DVB-H frequency band. The radiation patterns are a stable Figure-of-eight radiation pattern in the frequency range.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.481-489
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• 1993

The charge distribution is calculated to analyze the quasi-static impedance of periodic interdigital transducer taking into account the effect of infinite neighboring electrodes. The charge distribution can be represented by the element factor and array factor. The radiation conductance, susceptance and static capacitance of the input and output IDT's with arbitrary voltages are obtained by the charge distribution. The impedance of apodized IDT, is analyzed by multi-track model in which IDT is represented by the parallel connection of the uniform tracks. The calculated input and output impedances are in good agreement with the experimental results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.67-78
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• 2009

Radiation characteristics of microstrip patch antennas integrated with mushroom-like EBG structures in all directions and length direction on a substrate with the relative dielectric constant of 10 are systematically analyzed. As the substrate thickness increases, the effect of the surface wave on the input impedance and radiation pattern of a patch antenna increases. The effect of EBG structures on the input impedance of a patch antenna is negligible when the distances between EBG structures and the center of a patch antenna are 0.4 ${\gamma}_0$, 0.2 ${\gamma}_0$ and 0.1 ${\gamma}_0$ for the substrate thickness of 3.2 mm, 1.6 mm and 0.8 mm, respectively. The forward radiation is improved due to the suppression of surface wave when the periods of EBG structures integrated are larger than 2, 2, 3 periods for the substrate thickness of 3.2 mm, 1.6 mm and 0.8 mm, respectively. The effects of EBG structures on the radiation characteristics of a patch antenna integrated with EBG structures in all directions and length direction are similar.

• 전자공학회논문지 IE
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• v.48 no.3
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• pp.10-15
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• 2011

In the case of designing an acoustic transducer for high power application, we usually aim to transfer the source electric energy to the output acoustic energy as large as possible. For this purpose, we should match the impedance of the power amplifier to the impedance combined with the acoustic transducer impedance and the radiation impedance. Especially if we have electrical source with almost zero impedance, we need improve the power factor of the acoustic transducer in the load. In this paper, we propose a broad band impedance matching method by the improvement of power factor, which applies ABCD matrix.

• ETRI Journal
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• v.34 no.3
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• pp.454-457
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• 2012

A miniaturized planar digital video broadcasting terrestrial (DVB-T) antenna, which is composed of a patterned helical line, an open stub, and an impedance matching circuit on an FR4 (${\varepsilon}_r$=4.4) substrate for portable media player applications, is presented in this letter. The antenna has monopole-like, omni-directional radiation characteristics and a wide impedance bandwidth (VSWR<3) in the DVB-T band from 174 MHz to 230 MHz at the VHF band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.424-430
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• 2012

A ground radiation antenna is designed using a capacitor connected between two ground points by a strip line. This paper analyzes the variations of radiation performance when changing the capacitor position. The surface current distribution of the ground antenna was investigated as the capacitor position is changed, in order to demonstrate the effects on the impedance bandwidth and antenna efficiency. Our antenna is for the Wi-Fi application. It is verified that the capacitor at the end of the strip line provides a wide impedance bandwidth(7.2 % at the 2.45 GHz frequency) and good antenna efficiency(measured as 66 % averaged over the overall Wi-Fi frequency band).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.33-37
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• 2009

In this paper, a printed small Ultra-Wideband (UWB) antenna with directive radiation characteristics based on combination of electric-magnetic radiators is presented. The combinations of the electric and magnetic type antennas result in the directive radiation patterns for all observed UWB frequency band. Simple combination of dipole antenna and loop antenna is also presented to show that proper configuration of electric radiator and magnetic radiator can produces directive radiation characteristics. The target frequency is from 3.1 GHz to 10.6 GHz with size of $15\;mm{\times}31\;mm$. A proto-type of the combined antenna is simulated, fabricated and measured. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured VSWR curves. Also, the results show the directive radiation characteristics with small antenna form factor over the target frequency range.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2345-2350
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• 2014

In this paper, measurement methods for the characteristics of antennas for indoor digital TV (DTV), having 75-ohm port impedance, are introduced. Reference impedance of typical radio frequency (or microwave) systems and measurement equipments is 50 ohm. However, the reference impedance of antennas for indoor DTV is 75 ohm, and the characteristics of the antennas cannot be measured directly using the measurement equipments. Measurement methods, using test equipments with reference impedance of 50 ohm, for the characteristics(impedance, radiation patterns, and gain) of antennas designed to fit for 75 ohm port are introduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.45-46
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• 2014

In this paper, measurement methods for the characteristics of antennas for indoor digital TV (DTV), having 75-ohm port impedance, are introduced. Reference impedance of typical radio frequency (or microwave) systems and measurement equipments is 50 ohm. However, the reference impedance of antennas for indoor DTV is 75 ohm, and the characteristics of the antennas cannot be measured directly using the measurement equipments. Measurement methods, using test equipments with reference impedance of 50 ohm, for the characteristics(impedance, radiation patterns, and gains) of antennas designed to fit for 75 ohm port are introduced.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.466-469
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• 2004

In this paper, we improve the matching impedance of antennas by inserting parasitic slots on the ground plane of right-angle triangular slot antennas. The designed antennas characteristics are analyzed by using Finite Different Time Domain (FDTD) method, the specific design frequency is 10 GHz and match impedance is 50 ohms. Simulation results show that the efficient of return loss and radiation patterns are improved and enhance. In this case, the right-angle triangular slot antennas with parasitic slots have matching impedance better than antennas without parasitic slots.