• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.739-745
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• 2009

This paper presents a design for trapezoidal planar UWB(Ultra Wide-band) antenna using symmetry meander line to realize broad bandwidth at low frequency region. The size of proposed design antenna is $15.5{\times}21{\times}1.6mm^3$ and dielectric substrate considered in design has 4.4 of relative permittivity. The calculated bandwidth is from 1.31 GHz to 10.83 GHz and the measured return loss is 1.5 GHz to 10.6 GHz at -10 dB below, and satisfies with the UWB antenna's bandwidth. The simulated and measured radiation patterns show fine agreement with each other at each frequency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.7
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• pp.462-468
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• 2018

The piezoelectric energy harvesting characteristics of a trapezoidal cantilever generator with lead zirconate titanate (PZT) laminate were investigated with various Ag inner electrodes. The piezoelectric mode of operation was a transverse mode by using a planar electrode pattern. The piezoelectric cantilever generator was fabricated using trapezoidal cofired-PZT/Ag laminates by five specimens of 2, 3, 4, 7, and 13 layers of Ag. As the number of Ag electrodes increased, impedance and output voltage at resonant frequency significantly decreased, and capacitance and output current showed an increasing tendency. A maximum output power density of $7.60mW/cm^3$ was realized for the specimen with seven Ag layers in the optimal condition of acceleration (1.2 g) and resistive load ($600{\Omega}$), which corresponds to a normalized power factor of $5.28mW/g^2{\cdot}cm^3$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.768-775
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• 2017

Energy harvesting characteristics of trapezoidal piezoelectric cantilever generator, which has a lead zirconate titanate (PZT) laminate film, were compared by longitudinal (3-3) and transverse (3-1) modes. The PZT laminate film, fabricated by a conventional tape casting process, was cofired with Ag electrode at $850^{\circ}C$ for 2 h. A multi-layered Ag electrode by a planar pattern and an interdigitated pattern was applied to the PZT laminate to implement the 3-3 and 3-1 modes, respectively. The energy harvesting performance of the 3-3 mode trapezoidal piezoelectric cantilever generator was better than that of the 3-1 mode. An extremely high output power density of $26.7mW/cm^3$ for the 3-3 mode was obtained at a resonant frequency of 145 Hz under a load resistance of $50{\Omega}$ and acceleration of 1.3 G, which is ~3-times higher than that for the 3-1 mode. Therefore, the 3-3 mode is considered significantly efficient for application to high-performance piezoelectric cantilever generator.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.6
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• pp.473-478
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• 2021

This paper designed a wideband, high gain planar trapezoidal monopole antenna using backside frequency selective surface (FSS) according to the need for wideband and high gain antenna required in various fields such as rapidly increasing wireless communication, autonomous vehicles, 5G wireless communication and wideband applications. The proposed antenna uses a dual metallic to have a structural difference from the existing FSS. By solving the complexity of the design antenna using genetic algorithms (GA) and high frequency structural simulators (HFSS) simulations, the proposed antenna is not only produce a high efficiency but also presents a wide bandwidth of 3.52 to 5.92 GHz and a gain of 10.5 dBi over the entire bandwidth, with the highest gain of 11.8 dBi at 5.1 GHz. It has been confirmed that the gain increased 8.6 dBi as the 36% impedance bandwidth of 1.8 GHz compared to the existing antenna improved to the 50% impedance bandwidth of 2.4 GHz.