Browsing by Author "Pu, Ta Chun"

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A planar shaped-beam antenna for indoor wireless LAN access points
(2007-06-01)
Hwang, Ruey Bing
;
Pu, Ta Chun
;
電信工程研究所
;
Institute of Communications Engineering
A planar antenna is described that is made up of a;ne source embedded in a structure containing a metal reflector and a dielectric layer coated with metal strips. We have fabricated and measured the radiation characteristics, including the return loss and radiation pattern. In addition to the experimental studies, the rigorous mode-matching method incorporating the equivalent principle was employed to calculate the electromagnetic fields in the structure and the far-field radiation pattern, as well. Besides, the sensitivity analyses for the radiation pattern against the variations on the structure parameters and relative dielectric constant,,ere carefully carried out. The good agreement between the measured and calculated results was found. Combining the leak-waves and space-wave radiating from this structure, such a linearly polarized antenna can radiate a rectangular footprint of uniform electric-field strength, with 9% bandwidth around 11.4 GHz.
Omnidirectional stop band by using composite two dimensionally artificial crystal
(2007-08-01)
Hwang, Ruey Bing
;
Pu, Ta Chun
;
電信工程研究所
;
Institute of Communications Engineering
We present here a study of the wave propagation in a two-dimensionally (2D) periodic structure. The scattering of a plane wave by a 2D periodic structure is analyzed as a multilayer boundaryvalue problem. Specific examples are given to show quantitatively the stopband behaviors; in particular, a composite structure with different lattice patterns in cascade is shown to achieve the broad and omnidirection behavior of stop band. (c) 2007 Wiley Periodicals, Inc.