• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.362-368
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• 2023

In this paper, we presented the characteristics of the impulse signal which is applicable to the ultra-wideband antennas. In general, the width of the impulse has around sub nano or pico seconds in the time domain, where it corresponds to the wideband in the frequency domain. We confirmed by experiment that the impulse has around 130ps of the pulse width and bandwidth of 4GHz when 10MHz of sine wave excited as an input pulse. The fidelity factor was calculated in the time domain and -10dB bandwidth in the frequency domain was investigated for resistively loaded dipole antennas with different resistance per unit length. The received impulse signal through the wideband antennas is confirmed in the time and frequency domains that received pulse is to be similar to the generated impulse. The fidelity and bandwidth of the quantity value are 0.98 and 3.4GHz, respectively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.2
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• pp.93-98
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• 2024

This paper presents the method to extract the ultrawide-band (UWB) signal and proposes the simple impulse radar system for sensing real-based target within close-range area. The proposed impulse radar system consists of impulse generator, ultrawide-band antennas, function generator, and digital oscilloscope. It is verified by experiment that a differentiated Gaussian pulse is generated with 200ps of pulse width and corresponding spectrum from 0.3 to 4.7 GHz once a sinusoidal wave with 10MHz is excited. The Gaussian doublet is received by identical antennas and it is shown that the UWB pule width of 328ps and its spectrum is from 0.9 to 4.4 GHz. It is confirmed that the UWB pulse is extracted when the real-based targets such as circular target with 4cm radius and corner reflector are placed at the close-range area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.454-463
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• 2000

A method is presented to alter the geometry of the conventional linearly shaped wire antenna for increasing its bandwidth. The synthesis is two-demensionally symmetric and is based on the minimization of frequency-dependence of the boresight far-field electric field intensity. The current distribution on the wire is calculated by Galerkin method using pulse functions. The shaping limitation for wide-band characteristics is still found because of standing waves due to reflected waves from antenna ends. The limitation overcome by a distribution of resistive loads near ends of wire. The antenna loaded resistively has flat characteristics satisfying a power gain of $6.5\pm1.1$dBi and VSWR of at most 2 over 10:1 bandwidth. The results are verified by comparing with similar results for the conventional linear V-dipole.