A fundamental study is focused to investigate the power transmission efficiency of the wireless p... more A fundamental study is focused to investigate the power transmission efficiency of the wireless power transmission system by near-field coupling from a view point of antenna theory. Two types of antennas, dipole and loop antennas, are used as the transmitting antennas and receiving antennas for electrical near-field coupling and for magnetic near-field coupling, respectively. The relation is clarified between the power transmission efficiency and antenna geometry, antenna electrical size, impedance matching of the antennas, and ohmic loss in antennas and impedance matching circuits. Seveal observations have been obtained to demonstrate the influence on the power transmission efficiency from the impedance matching and ohmic loss in the wireless power transmission system by near-field coupling.
A new near-zero refractive-index metamaterial unit is proposed in this paper. The basic structure... more A new near-zero refractive-index metamaterial unit is proposed in this paper. The basic structure of the proposed unit consists of two face-to-face E-type microstrip lines, which connect to the background microstrip line by two vias through the crossbar of the E sharped microstrip line. The retrieved refractive-index, equivalent permittivity and permeability from scattering parameters are calculated. The results show that the real part of the refractive-index as well as the equivalent permittivity is near zero at the bandwidth from 10.5 GHz to 14.5 GHz. A Shelby lens based on the proposed metamaterial unit can perform negative refraction at the near-zero refractive-index bandwidth. Furthermore, a rectangular electromagnetic invisible cloak is designed and simulated based on the proposed metamaterial unit. The simulated results show that the rectangular cloak can make the cylinder with pure copper electromagnetic invisible, which validates the correctness of the proposed near-zero re...
A simultaneous measurement method using the modulated scattering element array is proposed to mea... more A simultaneous measurement method using the modulated scattering element array is proposed to measure the electromagnetic radiation which is instant and irregular. Each modulated scattering element (MSE) is excited by a local signal with different frequency, so that the received IF signal contains different frequency components which indicates the relative magnitude of the RF signal at positions of the MSEs, and all of the IF components are measured simultaneously by the broadband microwave receiver. Radiation pattern of a 2-element quarter wavelength monopole array is measured for evaluating the performance of the measurement method. It is found that good agreement of the measurement results is obtained between the present measurement and the conventional method.
A fundamental study is focused to investigate the power transmission efficiency of the wireless p... more A fundamental study is focused to investigate the power transmission efficiency of the wireless power transmission system by near-field coupling from a view point of antenna theory. Two types of antennas, dipole and loop antennas, are used as the transmitting antennas and receiving antennas for electrical near-field coupling and for magnetic near-field coupling, respectively. The relation is clarified between the power transmission efficiency and antenna geometry, antenna electrical size, impedance matching of the antennas, and ohmic loss in antennas and impedance matching circuits. Seveal observations have been obtained to demonstrate the influence on the power transmission efficiency from the impedance matching and ohmic loss in the wireless power transmission system by near-field coupling.
A new near-zero refractive-index metamaterial unit is proposed in this paper. The basic structure... more A new near-zero refractive-index metamaterial unit is proposed in this paper. The basic structure of the proposed unit consists of two face-to-face E-type microstrip lines, which connect to the background microstrip line by two vias through the crossbar of the E sharped microstrip line. The retrieved refractive-index, equivalent permittivity and permeability from scattering parameters are calculated. The results show that the real part of the refractive-index as well as the equivalent permittivity is near zero at the bandwidth from 10.5 GHz to 14.5 GHz. A Shelby lens based on the proposed metamaterial unit can perform negative refraction at the near-zero refractive-index bandwidth. Furthermore, a rectangular electromagnetic invisible cloak is designed and simulated based on the proposed metamaterial unit. The simulated results show that the rectangular cloak can make the cylinder with pure copper electromagnetic invisible, which validates the correctness of the proposed near-zero re...
A simultaneous measurement method using the modulated scattering element array is proposed to mea... more A simultaneous measurement method using the modulated scattering element array is proposed to measure the electromagnetic radiation which is instant and irregular. Each modulated scattering element (MSE) is excited by a local signal with different frequency, so that the received IF signal contains different frequency components which indicates the relative magnitude of the RF signal at positions of the MSEs, and all of the IF components are measured simultaneously by the broadband microwave receiver. Radiation pattern of a 2-element quarter wavelength monopole array is measured for evaluating the performance of the measurement method. It is found that good agreement of the measurement results is obtained between the present measurement and the conventional method.
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Papers by Qiang Chen