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ABSTRACT: A dielectric hybrid-mode horn has been analyzed theoretically. The horn can support a balanced hybrid HE mode. The fields under the balanced hybrid condition have been expressed. By optimizing the structure parameters, the fraction of the power radiated into the fundamental Gaussian mode can reach about 98% over a wide frequency range in 3-mm band. Drawbacks are the effects of dielectric losses. Thus the new horn represents an attractive alternative to the corrugated horn for forming the Gaussian beam in millimeter-wave band. © 1993 John Wiley & Sons, Inc.
Microwave and Optical Technology Letters 03/2007; 6(8):475 - 478. · 0.62 Impact Factor
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ABSTRACT: The electromagnetic field modes in partial-height ferrite circulators are classified into two categories: volume modes and surface modes. Their properties are described in detail. The method of expanding the circulator bandwidth at the millimeter wave band is investigated. A set of theoretical results are calculated for a n = 2 Chebyshev response. A Ka-band circulator is designed. The measured minimum isolation is 15 dB over a 9-GHz bandwidth. The experimental result and theoretical prediction are similar.
Microwave and Optical Technology Letters 01/2007; 1(6):200 - 208. · 0.62 Impact Factor
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ABSTRACT: In this article, an improved iterative arithmetic of the symmetric successive over-relaxation preconditioning biconjugate-gradient algorithm (ISSOR-PBCG) is utilized to solve the 3D edge FEM equations derived from the time-harmonic electromagnetic-field boundary value problems. Several typical structures have been analyzed, and the computation time is compared with that of other algorithms such as biconjugate-gradient (BCG) algorithm and the conventional symmetric successive over-relaxation preconditioning biconjugate- gradient algorithm (SSOR-PBCG). The CPU time saved using the ISSOR-PBCG algorithm is nearly 27% and 65.5%, as compared with that using the SSOR-PBCG and the BCG algorithm. It can be seen that the ISSOR-PBCG algorithm is efficient for edge FEM equation sets derived from large-scale time-harmonic electromagnetic-field problems. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.
International Journal of RF and Microwave Computer-Aided Engineering 08/2006; 16(5):496 - 501. · 0.59 Impact Factor
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Electromagnetics 02/2006; 26(2):123-129. · 0.79 Impact Factor
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ABSTRACT: A novel approach, which is based on an improved reverse-microscope system (IRMS), for measuring inhomogeneity and irregularity of dielectric plate was proposed and simulated at millimeter wavelengths. The IRMS is designed carefully so as to produce a thin beam, which occupy a smaller area than Gaussian beam does. Both finite difference time domain (FDTD) method and finite element method (FEM) are used to verify the validity of IRMS with higher spatial resolution. Therefore, the IRMS can be used to measure the permittivity and thickness of the plate, which may be different from cell to cell and may not be in planar form. Then numerical simulation results based on the FDTD method were presented, which is depicted as images to show the variance of the permittivity and thickness of dielectric plate and compared with that from Gaussian beam. The advantage of IRMS over Gaussian beam is demonstrated.
Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
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ABSTRACT: An analysis of waveguide multi-port discontinuities is presented using an approach combining the mode expansion method and finite element method, which is based on the weak form of the Helmholtz equation. The expression of the weak form of the Helmholtz equation containing anisotropic media is derived, and its reduced form without anisotropic media is also given. Mode expansion other than perfectly matched layer (PML) is used to truncate the computing space of finite elements. Junction circulators loaded with different shape ferrite posts and power dividers are studied as examples. The calculation results of the scattering parameters of these structures are shown and compared respectively to those in the literature and experiments. Consistency has been observed and their validity is verified.
IEE Proceedings - Microwaves Antennas and Propagation 01/2005; · 0.49 Impact Factor
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ABSTRACT: A new approach for the analysis of waveguide multiports discontinuities is presented in this paper. This approach is a combined method of the mode-expansion method and finite-element method, which is based on the weak form of the Helmholtz equation. We use a mode expansion technique other than PML to truncate the computing space of finite element. Multiport structures such as H-Plane forked T-junction, waveguide loaded with two dielectric posts, and E-plane filter are studied as examples. The calculated results of these structures are shown and compared, respectively, to those in references. Good agreement between them is observed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 173–177, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20411
Microwave and Optical Technology Letters 08/2004; 43(2):173 - 177. · 0.62 Impact Factor
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ABSTRACT: Magic tee is a widely used component in microwave systems; the four arms of conventional magic tee direct at four different directions, which give inconveniences to the assemblage of a system. In this paper, a broad-wall slot directional coupler and an E-plane dielectric loaded waveguide phase shifter is used to form a magic tee with four arms in the same E-plane. The magic tee is analyzed exactly with mode match method; and the simulated annealing method is used to optimize the performance of the magic tee. Simulation results are presented, which show good performance.
International Journal of Infrared and Millimeter Waves 05/2004; 25(6):939-958. · 0.58 Impact Factor
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ABSTRACT: Diffractive lens have many advantages over refractive lens at millimeter waves band, such as thin, light and low dielectric loss and so on. However, diffractive lens have chromatic aberration, that is, focusing performance of diffractive lens is frequency dependent. In this report, a dual frequencies diffractive lens is developed, which can work at 8mm band and 3mm band, based on the harmonic diffractive lens techniques. Experiments show it has almost same focusing performance at 8mm band and 3mm band.
International Journal of Infrared and Millimeter Waves 04/2004; 25(5):827-836. · 0.58 Impact Factor
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ABSTRACT: The fields in the focal space of two types of a phase-only diffractive lens, which is illuminated by a plane wave, are analyzed with the FDTD method and the Stratton–Chu formula. Both oblique and perpendicular incidence are considered. The diffraction efficiency is calculated. The results of experiments carried out to verify the correctness of the calculation are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 396–401, 2001.
Microwave and Optical Technology Letters 10/2001; 31(5):396 - 401. · 0.62 Impact Factor
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ABSTRACT: The fields refracted by circular symmetric hyperbolic lens illuminated by a linearly polarized plane wave are calculated from the induced surface currents. It is shown that the fields in the axial region approximate to the fields in the aperture of corrugated horn under balanced hybrid condition. The image structures for different focal ratio are compared with the classical Airy pattern, deduced by scalar analysis, of optical focusing systems. The coupling between the lens and a corrugated horn at different position on focal plane are presented. The lens resolution and pix numbers are evaluated.
International Journal of Infrared and Millimeter Waves 09/1999; 20(10):1843-1854. · 0.58 Impact Factor
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ABSTRACT: The far-field patterns of an extended
hemispherical-lens/objective-lens antenna system fed by a double-slot
antenna is computed using the hybridisation of ray-tracing and
diffraction techniques. The difference patterns computed for a monopulse
antenna are also presented. The computation results show that this
antenna has good performance. Although the double-slot antenna is used
as a feed antenna, other antennas such as slot-ring or bow tie antennas
can also be used. This antenna can be used in many millimetre-wave
systems
IEE Proceedings - Microwaves Antennas and Propagation 09/1998; · 0.49 Impact Factor
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ABSTRACT: In this paper an analysis of the far-field pattern of a focal-plane array in the case of two different lenses, a coma-free lens and a hyperbolic lens, and their comparison, are presented. Ray tracing and aperture integration are used. The calculated field pattern at W band is presented. The focal-plane elements are assumed to be corrugated horn. The f / D of the lens is 1.3. The coma-free lens is designed by step integration. The calculation results show that the coma-free lens is superior to the hyperbolic lens in the imaging performance. The coma-free lens can contain more pixels under the condition that the beam size and beam quality are almost constant over the range of angles scanned and the differences among beams gain less 1.8 dB. The aperture efficiency and directivity are also presented.
International Journal of Infrared and Millimeter Waves 03/1998; 19(4):673-685. · 0.58 Impact Factor
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ABSTRACT: The far-field pattern of the extended hemispherical lens/objective lens antenna system is analyzed by ray tracing and field integration methods. Double slot antennas are placed on the dielectric lens. Calculation results are presented. It is shown that this antenna has a good radiation property
Microwave Conference Proceedings, 1997. APMC '97, 1997 Asia-Pacific; 01/1998
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ABSTRACT: In this paper, the far-field patterns are investigated for double-slot antenna array placed on extended hemispherical lenses.
The radiation patterns of the extended hemispherical lens fed by single double-slot antenna or double-slot antenna array are
computed using ray-tracing inside the dielectric lens and electric and magnetic field integration on the spherical dielectric
surface. The computation results show that the sharp null of the difference pattern is below -37dB.
International Journal of Infrared and Millimeter Waves 03/1997; 18(4):811-825. · 0.58 Impact Factor
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ABSTRACT: In this paper the exact analysis on the waveguide junction circulator and Faraday rotator are presented in detail. The correctness of analysis is demonstrated by its successful prediction about the performance of the devices. Many calculation results are presented by comparing with the experimental results. The approaches of expanding bandwidth of devices at W band are stated.
International Journal of Infrared and Millimeter Waves 11/1996; 17(12):2035-2131. · 0.58 Impact Factor
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ABSTRACT: Summary form only given. In this paper the far field pattern of a millimeter wave focal plane array with a lens is calculated with a hybrid approach that uses ray tracing through the lens and diffraction calculation of propagation to the far-field. In order to keep beam size and beam quality from the aberration of the lens, a coma-free lens, that is designed by step integrate, is adopted. The field pattern calculated is presented
Millimeter Wave and Far Infrared Science and Technology, 1996. Proceedings. 4th International Conference on; 09/1996
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ABSTRACT: In this communication a note on the coupling efficiency between an antenna and a Gaussian beam is presented. The coupling efficiency is calculated using a normalized inner product between the antenna radiation pattern and the Gaussian-beam pattern in the angular domain or alternatively, between the electric field at the antenna aperture and a two-dimensional field representation of a Gaussian beam. The calculations of the coupling efficiency from both methods are compared for different aperture size in wavelength
Millimeter Wave and Far Infrared Science and Technology, 1996. Proceedings. 4th International Conference on; 09/1996
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ABSTRACT: A quasioptical ferrite switch is proposed as an essential building block in millimeter wave systems. In this communication the configuration of the quasioptical ferrite switch is described. The performance of the switch is calculated, and its application in radiometric system is pointed out. The isolation of such device is greater than 30 dB and insertion loss less than 1.0dB over whole W band.
International Journal of Infrared and Millimeter Waves 06/1996; 17(7):1193-1198. · 0.58 Impact Factor
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ABSTRACT: In this communication a note on the coupling efficiency between an antenna and a Gaussian beam is presented. The calculations of the coupling efficiency from both methods, a nomorlized inner product between the antenna radiation pattern and the Gaussian-beam pattern or alternatively, between the electric field at the antenna aperture and a two-dimensional field representation of a Gaussian beam, are compared for different aperture size in wavelength. How a correct solution can be gotten is stated.
International Journal of Infrared and Millimeter Waves 06/1996; 17(7):1235-1241. · 0.58 Impact Factor
