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Your search keyword '"Hyunchul Ku"' showing total 2 results
Start Over Author "Hyunchul Ku" Journal journal of electromagnetic engineering and science
2 results on '"Hyunchul Ku"'

1. Sidelobe Suppression Beamforming Using Tapered Amplitude Distribution for a Microwave Power Transfer System with a Planar Array Antenna

Author

Inho Park, Chulhun Seo, and Hyunchul Ku

Subjects
array factor, digital beamforming, microwave power transfer, sidelobe suppression, wireless power transfer, Electrical engineering. Electronics. Nuclear engineering, TK1-9971, Electricity and magnetism, QC501-766
Abstract

This paper proposes a sidelobe suppression beamforming scheme using tapered amplitude distribution for microwave power transfer (MPT) with a two-dimensional planar array antenna (PAA). To overcome the undesirable effects of sidelobes, the magnitude of the sidelobes can be lowered by manipulating the amplitude distribution of the PAA. By analyzing the array factor of the PAA, we expressed the amplitude distribution as the product of two one-dimensional vectors. Moreover, we developed a method for obtaining these vectors from an expected sidelobe level (SLL). We used the Chebyshev taper, which has a higher directivity than other distributions given an expected SLL, for the amplitude distribution. To verify the proposed method, we designed and implemented a digital beamforming system with a 4 × 4 transmitter (Tx) array and a receiver (Rx) at 5.8 GHz. Compared with a uniform amplitude distribution, the proposed method reduced the SLL by 7.5 dB but the received RF power by only 0.6 dB. We compared the performance of the proposed MPT system with the results of previous studies.

Published
2022
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2. Analysis and Optimization of Wireless Power Transfer Efficiency Considering the Tilt Angle of a Coil

Author

Wei Huang and Hyunchul Ku

Subjects
Tilt Angle, Computer science, Acoustics, 020208 electrical & electronic engineering, Mutual Inductance, 020206 networking & telecommunications, 02 engineering and technology, Inductance, Power Transfer Efficiency, Tilt (optics), Electromagnetic coil, Coupling Coefficient, 0202 electrical engineering, electronic engineering, information engineering, Wireless Power Transfer, lcsh:Electrical engineering. Electronics. Nuclear engineering, Wireless power transfer, lcsh:TK1-9971, Coupling coefficient of resonators
Abstract

Wireless power transfer (WPT) based on magnetic resonant coupling is a promising technology in many industrial applications. Efficiency of the WPT system usually depends on the tilt angle of the transmitter or the receiver coil. This work analyzes the effect of the tilt angle on the efficiency of the WPT system with horizontal misalignment. The mutual inductance between two coils located at arbitrary positions with tilt angles is calculated using a numerical analysis based on the Neumann formula. The efficiency of the WPT system with a tilted coil is extracted using an equivalent circuit model with extracted mutual inductance. By analyzing the results, we propose an optimal tilt angle to maximize the efficiency of the WPT system. The best angle to maximize the efficiency depends on the radii of the two coils and their relative position. The calculated efficiencies versus the tilt angle for various WPT cases, which change the radius of RX (r2 = 0.075 m, 0.1 m, 0.15 m) and the horizontal distance (y = 0 m, 0.05 m, 0.1 m), are compared with the experimental results. The analytically extracted efficiencies and the extracted optimal tilt angles agree well with those of the experimental results.

Published
2018
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