Browsing by Author "Sheen, JW"

Now showing 1 - 9 of 9

An improved dynamic model in integral equation methods for the characterization of discontinuities in planar circuits
(1996-07-01)
Sheen, JW
;
Lin, YD
;
電信工程研究所
;
Institute of Communications Engineering
An efficient method to improve the integral equations method is presented in this article. A delta gap source generator and the fundamental mode sampling technique are employed. By employing this modified method, observation of the SWR and the creation of a large matrix in the conventional method employing a delta gap source generator are not necessary. Also, the modeling complexity and the time-consuming computation of the conventional method, which employs the semiinfinite traveling-wave mode, are avoided. In this article we use the coplanar waveguide short-end discontinuity as an example to describe this method in the spectral domain. Moreover, numerical results are compared with our experimental data and they show good agreement. (C) 1996 John Wiley & Sons, Inc.
An improved dynamic model in integral equation methods for the characterization of discontinuities in planar circuits
(1996-07-01)
Sheen, JW
;
Lin, YD
;
交大名義發表
;
傳播研究所
;
National Chiao Tung University
An efficient method to improve the integral equations method is presented in this article. A delta gap source generator and the fundamental mode sampling technique are employed. By employing this modified method, observation of the SWR and the creation of a large matrix in the conventional method employing a delta gap source generator are not necessary. Also, the modeling complexity and the time-consuming computation of the conventional method, which employs the semiinfinite traveling-wave mode, are avoided. In this article we use the coplanar waveguide short-end discontinuity as an example to describe this method in the spectral domain. Moreover, numerical results are compared with our experimental data and they show good agreement. (C) 1996 John Wiley & Sons, Inc.
Analysis and design of feeding structures for microstrip leaky wave antenna
(1996-09-01)
Lin, YD
;
Sheen, JW
;
Tzuang, CKC
;
交大名義發表
;
傳播研究所
Three arrangements of the feeding structure for the excitation of a microstrip leaky wave antenna are proposed and investigated in this paper, A full-wave spectral domain integral equation method combined with the fundamental mode sampling technique is applied to determine the reflection coefficient of the excitation source. Tabulation technique is used to reduce the computational effort. Dependence on structural parameters such as line width, line spacing and overlap length is fully analyzed to obtain the design criteria for a microstrip leaky wave antenna. Additionally, an experimental setup is used to check the validity of our numerical results and verify the radiation nature of the microstrip line first higher-order mode.
Broadband tapered microstrip leaky-wave antenna
(2003-08-01)
Hong, WC
;
Chen, TL
;
Chang, CY
;
Sheen, JW
;
Lin, YD
This study proposes a novel scheme based on the characteristics of leaky-wave antennas for the empirical design of broadband tapered microstrip leaky-wave antennas. This scheme can explain and approximately model the radiation characteristics of a linearly tapered leaky-wave microstrip antenna. A broadband feeding structure that uses the balanced and the inverted balanced microstrip lines to form a pair of broadband baluns is also presented. The measured return loss of the inverted balanced microstrip lines has a VSWR less than or equal to 2 from dc to 18.6 GHz and that of the back-to-back feeding structures has a VSWR less than or equal to 2 from 2.2 to 18.6 GHz. This feeding structure can be used to feed a broadband planar leaky-wave antenna with a fixed mainbeam that uses the tapered microstrip structure. The measured bandwidth of the antenna for a VSWR less than or equal to 2 exceeds 2.3:1.
Microstrip-fed microstrip second higher order leaky-mode antenna
(2001-06-01)
Chen, TL
;
Lin, YD
;
Sheen, JW
;
傳播研究所
;
Institute of Communication Studies
With the appropriate placement of the slots and via holes, the microstrip second higher order leaky-mode antenna Fed by a microstrip is presented, Two main beams with titled angles from the strip are measured in the predicted radiation leaky band. The leaky band of the microstrip second higher order mode is deduced from the characteristics of the propagation constants that are calculated by the spectral domain analysis. The proposed feeding method provides a direct connection with the circuits based on the microstrip line.
Mode distinction and radiation-efficiency analysis of planar leaky-wave line source
(1997-10-01)
Lin, YD
;
Sheen, JW
;
交大名義發表
;
傳播研究所
;
National Chiao Tung University
Using the first microstrip-line higher order mode as an example, mode distinction and radiation efficiency of leaky-wave line sources in the radiation region are presented in this paper, The spectral-domain approach is used to calculate complex power hows, leaving the line source in the transverse directions and those guided down the line source. Ply observing the behavior of these complex power flows in different frequency regions, the leaky-wave line source can be distinguished into the antenna mode and the reactive mode in the radiation region, Experimental results are shown to confirm this mode distinction, Moreover, by comparing the power carried away by the surface and the space waves, radiation efficiency of the first microstrip-line higher order mode of various structural parameters is analyzed. The microstrip line is more efficient as a leaky-wave line source when its substrate is thin, the dielectric constant of the substrate is low, and the antenna main,cam is away from the end-fire direction.
Propagation characteristics of the slotline first higher order mode
(1998-11-01)
Sheen, JW
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
The propagation characteristics of the slotline first higher order mode are presented in detail in this paper. It is found that the attenuation constants and the radiation band of this first higher order mode are larger than those of the microstripline first higher order mode. Dependence of the propagation characteristics on structural parameters and the effect of finite-conductor planes are analyzed. The propagation characteristics of the surface-wave-like modes are also discussed. In order to avoid inadvertent excitation of these surface-wave-like modes in antenna applications, the current and field distributions of the slotline first higher order mode and the surface-wave-like modes are compared and discussed. Excitation of the slotline first higher order mode was conducted by feeding the slotline with a coplanar waveguide and microstrip line. Experimental results show good agreement with our numerical results, and also confirm the existence of the slotline first higher order mode.
Surface-wave-like mode in slot line
(1996-07-01)
Sheen, JW
;
Lin, YD
;
電信工程研究所
;
Institute of Communications Engineering
Propagation properties of the surface-wave-like mode in slot line are investigated with the spectral domain analysis, This surface-wave-like mode is an odd dominant mode with a magnetic wall symmetric plane placed at the center of the slot, Its field distribution is similar to that of the TM(0) mode supported by the surrounding structure, It exists in the lower frequency regime and evolves into a nonphysical and nonspectral real mode in the higher frequency regime, Unlike other surface-wave-like modes in planar transmission line, the surface-wave-like mode in slot line does not evolve into a leaky mode.
Surface-wave-like mode in slot line
(1996-07-01)
Sheen, JW
;
Lin, YD
;
交大名義發表
;
傳播研究所
;
National Chiao Tung University
Propagation properties of the surface-wave-like mode in slot line are investigated with the spectral domain analysis, This surface-wave-like mode is an odd dominant mode with a magnetic wall symmetric plane placed at the center of the slot, Its field distribution is similar to that of the TM(0) mode supported by the surrounding structure, It exists in the lower frequency regime and evolves into a nonphysical and nonspectral real mode in the higher frequency regime, Unlike other surface-wave-like modes in planar transmission line, the surface-wave-like mode in slot line does not evolve into a leaky mode.