An efficient expression of the effective permittivities along x-, y-, z-direction is obtained by ... more An efficient expression of the effective permittivities along x-, y-, z-direction is obtained by analogy with the circuit concept of series–parallel connection of capacitance. Under the condition of numerical stability, the approximate formulae of effective permittivities for various inhomogeneous cell mesh are combined with the Finite Difference Time Domain (FDTD) scheme of arbitrary spatial cell size to calculate resonant frequency of 3-D cavity. The results are in agreement with that of conventional FDTD method, but the proposed method can save computing time and memory.
The dominant mechanisms of the degradation are different. (a) The electric field affects the spat... more The dominant mechanisms of the degradation are different. (a) The electric field affects the spatial distribution of mobile ions; (b) the light field changes the mobile ion densities and drives the ion migration; (c) the heat field results in material decomposition.
Two-dimensional (2D) materials have been demonstrated to be promising candidates to design high p... more Two-dimensional (2D) materials have been demonstrated to be promising candidates to design high performance photodetector owing to their strong light-matter interaction. However, the performance of 2D material photodetectors is still...
2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
ABSTRACT The paper reports recent improvements in the performance of printed circularly-polarized... more ABSTRACT The paper reports recent improvements in the performance of printed circularly-polarized terminal antennas. These advances include the miniaturization of printed circularly-polarized geometries, simplification of geometries which provide dual circular-polarization, widening of the axial-ratio bandwidth, as well as increasing the axial-ratio beamwidth.
The 8th European Conference on Antennas and Propagation (EuCAP 2014), 2014
ABSTRACT The paper reports miniaturization of recently introduced planar omnidirectional circular... more ABSTRACT The paper reports miniaturization of recently introduced planar omnidirectional circularly polarized antennas. The technique relies on folding the antennas patch underneath itself, decreasing overall footprint. The connectivity between layers is provided by vias, enabling cost efficient PCB manufacturing techniques. The average axial ratio in the xz-plane is less than 3 dB in the band of 2.392 to 2.407 GHz. This is better than previously reported antennas of this type.
Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, 2012
ABSTRACT A wideband unidirectional circularly polarized antenna is proposed for Global Positionin... more ABSTRACT A wideband unidirectional circularly polarized antenna is proposed for Global Positioning System (GPS) and Galileo Systems. The antenna consists of a printed dipole-like element, spaced from a planar reflector. The fed element comprises a printed asymmetrical dipole with an open-ended slot between the feed lines. The operating frequency range covers the GPS system (L1, L2), GLONASS and Galileo system (E5, E6, E1-E2-L1). A parametric study of key parameters including reflector size and spacing are discussed. The impedance bandwidth, axial-ratio and gain are analyzed.
An efficient expression of the effective permittivities along x-, y-, z-direction is obtained by ... more An efficient expression of the effective permittivities along x-, y-, z-direction is obtained by analogy with the circuit concept of series–parallel connection of capacitance. Under the condition of numerical stability, the approximate formulae of effective permittivities for various inhomogeneous cell mesh are combined with the Finite Difference Time Domain (FDTD) scheme of arbitrary spatial cell size to calculate resonant frequency of 3-D cavity. The results are in agreement with that of conventional FDTD method, but the proposed method can save computing time and memory.
The dominant mechanisms of the degradation are different. (a) The electric field affects the spat... more The dominant mechanisms of the degradation are different. (a) The electric field affects the spatial distribution of mobile ions; (b) the light field changes the mobile ion densities and drives the ion migration; (c) the heat field results in material decomposition.
Two-dimensional (2D) materials have been demonstrated to be promising candidates to design high p... more Two-dimensional (2D) materials have been demonstrated to be promising candidates to design high performance photodetector owing to their strong light-matter interaction. However, the performance of 2D material photodetectors is still...
2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
ABSTRACT The paper reports recent improvements in the performance of printed circularly-polarized... more ABSTRACT The paper reports recent improvements in the performance of printed circularly-polarized terminal antennas. These advances include the miniaturization of printed circularly-polarized geometries, simplification of geometries which provide dual circular-polarization, widening of the axial-ratio bandwidth, as well as increasing the axial-ratio beamwidth.
The 8th European Conference on Antennas and Propagation (EuCAP 2014), 2014
ABSTRACT The paper reports miniaturization of recently introduced planar omnidirectional circular... more ABSTRACT The paper reports miniaturization of recently introduced planar omnidirectional circularly polarized antennas. The technique relies on folding the antennas patch underneath itself, decreasing overall footprint. The connectivity between layers is provided by vias, enabling cost efficient PCB manufacturing techniques. The average axial ratio in the xz-plane is less than 3 dB in the band of 2.392 to 2.407 GHz. This is better than previously reported antennas of this type.
Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, 2012
ABSTRACT A wideband unidirectional circularly polarized antenna is proposed for Global Positionin... more ABSTRACT A wideband unidirectional circularly polarized antenna is proposed for Global Positioning System (GPS) and Galileo Systems. The antenna consists of a printed dipole-like element, spaced from a planar reflector. The fed element comprises a printed asymmetrical dipole with an open-ended slot between the feed lines. The operating frequency range covers the GPS system (L1, L2), GLONASS and Galileo system (E5, E6, E1-E2-L1). A parametric study of key parameters including reflector size and spacing are discussed. The impedance bandwidth, axial-ratio and gain are analyzed.
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Papers by Xiulong Bao