Browsing by Author "Peng, ST"

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A back-to-back dual-beam active microstrip leaky-wave antenna array with mode-switching capability
(2000-02-05)
Hu, CC
;
Jou, CF
;
Wu, JJ
;
Peng, ST
;
傳播研究所
An X-band two-element back-to-back coupled-oscillator-driven spatial power-combining microstrip leaky-wave antenna array is developed, which has a dual-beam radiation pattern and mode-switching capability. Two Gunn diode CPW oscillators are placed on the back side of the substrate, each driving two back-to-back microstrip leaky-wave antenna pairs in opposite directions for dual-beam operation. This active antenna array is able to produce sum and difference patterns between the in-phase and 180 degrees out-of-phase mode by controlling the bias voltages of the Gunn diodes. (C) 2000 John Wiley & Sons, Inc.
A CPW-to-Slotline active gunn diode leaky wave antenna
(1998)
Lee, SH
;
Wu, JJ
;
Peng, ST
;
Hu, CC
;
Jou, CF
A X-band coplanar waveguide (CPW) to slotline couple feeding active microstrip leaky wave antenna using Gunn-diode oscillator as source is demonstrated. The method to excite the first higher order mode of the microstrip leaky wave antenna is to put the CPW-to-slotline transition underneath the middle of the microstrip line, and the oscillator circuit and radiating element are separated by a ground plane. The measured angle of the maximum beam direction of active antenna is at 72 degrees for the active Gunn oscillator frequency of 11.218 GHz; This prototype of active leaky wave antenna feeding by Gunn diode oscillator with CPW-to-slotline structure can be easily scaled up to millimeter wave frequency region.
A simple formulation for complex modes of image lines
(1996)
Peng, ST
;
Wu, JJ
;
電信工程研究所
;
Institute of Communications Engineering
Active asymmetrically feeding dual-beam leaky-wave antenna
(1998)
Wang, CJ
;
Jou, CF
;
Wu, JJ
;
Peng, ST
;
傳播研究所
An active-integrated dual-beam scanning leaky-wave antenna design is developed in this paper. A varactor-tuned oscillator HEMT VCO, an active source, integrates with an X-band two-terminal asymmetrically feeding microstrip leaky-wave antenna on the same plane. This approach creates a dual-beam radiation pattern and has the advantages of multi-direction and no reflected wave caused by the open end of the radiating element, as compared to a traditionally single-terminal feeding leaky-wave antenna. Measured results on the experimental antenna show that the total scanning angle of two beams of this antenna configuration is approximately 44 degrees The maximum Effective Isotropic Radiated Power (EIRP) are. close to 17.5 dBm for the right beam and 16.67 dBm for the left beam at 10.4 GHz,and the power difference between the two beams is less than 1 dB.
An active microstrip antenna for satellite communication
(2000)
Wang, CJ
;
Jou, CF
;
Wu, JJ
;
Peng, ST
;
傳播研究所
An active microstrip antenna for the satellite communication is developed in this paper. A varactor-tuned oscillator HEMT VCO, an active source, integrates with an X-band two-terminal asymmetrically feeding microstrip leaky-wave antenna on the same plane. This approach creates a dual-beam radiation pattern and has the advantages of multi-direction and suppression of the reflected wave caused by the open end of the radiating element, as compared to a traditionally single-terminal feeding leaky-wave antenna. Measured results on the experimental antenna show that the total scanning angle of two beams of this antenna configuration is approximately 44 degrees. The maximum Effective Isotropic Radiated Power (EIRP) are close to 17.5 dBm for the right beam and 16.67 dBm for the left beam at 10.4 GHz, and the power difference between the two beams is less than 1 dB. An asymmetrically beam-scanning leaky-wave antenna is also shown in this presentation.
Analysis of plane-wave scattering by bigratings
(1998)
Peng, ST
;
Hwang, RB
;
電信工程研究所
;
Institute of Communications Engineering
We present here a rigorous analysis of the plane-wave scattering by a class of bigratings, each of which consists of two separated gratings that may have different periods and different orientations. Inherently, this is a three-dimensional boundary value problem, regardless of the incidence condition. An exact formulation based on the method of mode matching is carried out, taking into account the effect of polarization couplings. Numerical results are shown for identifying physical phenomena associated with the class of bigrating structures. In particular, Wood's anomalies in the presence of a bigrating are carefully examined and the results are interpreted in terms of those well known for single gratings.
Anomalous absorption of resonance-type periodic structures
(2000)
Peng, ST
;
Hwang, RB
;
Shih, HY
;
交大名義發表
;
National Chiao Tung University
We present here a study on scattering characteristics of resonance-type periodic structures, taking into account the effects of structure dispersion and material loss. The phenomena of anomalous absorption are systematically investigated on the basis of the guiding characteristics of the structures. In particular, the effect of dispersion is carefully examined.
Coplanar waveguide to coplanar strips fed active leaky-wave antenna
(1998-01-01)
Hu, CC
;
Jou, CF
;
Wang, CJ
;
Lee, SH
;
Wu, JJ
A new active coplanar waveguide (CPW) to coplanar strips (CPS) fed microstrip leaky-wave antenna is developed, which integrated with a Gunn diode as active source. The CPW-CPS balun is used to excite the first higher order mode of the microstrip leaky-wave antenna. The active leaky-wave antenna has maximum EIRP of 20.4 dBm at 9.759 GHz. The Gunn oscillator frequency is controlled by tuning the Gunn DC bias and the beam scanning is demonstrated. The measured scanning angle agrees with the prediction, it is close to 12 degrees as the oscillator frequency tuned from 9.84 GHz to 9.61 GHz. The coplanar structure allow easy integration of many solid-state devices. It is suitable for monolithic power combining and millimeter wave applications.
Current research programs in Taiwan on guided and leaky waves
(1997)
Peng, ST
;
電信工程研究所
;
Institute of Communications Engineering
This paper reviews the research on guided and leaky waves that is being conducted in Taiwan. Both uniform and periodic structures are covered, but an emphasis is placed on the novel aspects of gratings, as they are rarely treated in the literature.
Distribution of current induced on metal-strip gratings by plane wave
(1998-06-01)
Shiao, CM
;
Peng, ST
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we present a rigorous analysis of current distribution induced on a metal-strip grating by an incident plane wave. The metal strips of the grating are characterized by a complex permittivity, with a large imaginary part to account for their finite conductivity. Such a scattering problem is formulated by the mode-matching method to determine the scattered fields everywhere, so that the volume distribution of current within a metal strip can be explicitly obtained, Numerical results are given to illustrate the effects of the dielectric constant of the surrounding media, as well as the incident angle and polarization on the current distribution induced by an incident plane wave. The air and metal modes form the basis for physical explanations of the numerical results obtained.
Edge currents on metal strip gratings
(1997)
Shiao, CM
;
Peng, ST
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
We present here a rigorous analysis of current distribution induced on metal-strip grating by an incident plane wave. The grating is characterized by a complex permittivity, with a large imaginary part to account for the finite conductivity of the metal strips. Such a scattering problem is formulated by the method of mode matching to determine the scattered fields everywhere, so that the volume distribution of current within a metal strip can be explicitly obtained. In particular, in the cast of TE-mode incidence, edge currents on the metal. strips are examined, with respect to the conductivity and thickness of the grating as well as the incident wavelength. Our results agree well with those of the quasi-static approximation in the low-frequency limit, while noticeable deviations are observed in the high-frequency end.
Effect of finite conductivity on dispersion characteristics of grating waveguide
(1998-01-01)
Shiao, CM
;
Peng, ST
;
電信工程研究所
;
Institute of Communications Engineering
We present here a systematic investigation of dielectric waveguide loaded with a metal-strip grating which is realistically characterized by a complex dielectric constant with a negative imaginary part to account for the finite conductivity of the metal strips. The method of mode matching is employed to solve such a boundary-value problem, and the effects of the structure parameters on the dispersion characteristics are critically examined, with a particular attention directed toward the attenuation constant due to the Bragg reflection, radiation and absorption of the grating waveguide.
Effect of finite conductivity on dispersion characteristics of grating waveguide
(1998-01-01)
Shiao, CM
;
Peng, ST
;
電信工程研究所
;
Institute of Communications Engineering
We present here a systematic investigation of dielectric waveguide loaded with a metal-strip grating which is realistically characterized by a complex dielectric constant with a negative imaginary part to account for the finite conductivity of the metal strips. The method of mode matching is employed to solve such a boundary-value problem, and the effects of the structure parameters on the dispersion characteristics are critically examined, with a particular attention directed toward the attenuation constant due to the Bragg reflection, radiation and absorption of the grating waveguide.
Guidance characteristics of two-dimensionally periodic impedance surface
(1999-12-01)
Hwang, RB
;
Peng, ST
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
In this paper, we present an exact formulation for the three-dimensional boundary-value problem of waveguiding by a two-dimensional periodic impedance surface in a uniform medium. The dispersion characteristics of such a structure are rigorously analyzed in terms of the complete set of both TE- and TM-polarized plane waves in the uniform medium. The results are systematically expressed in the form of the Brillouin diagram; thereby, in comparison to the one-dimensional case, a host of new and interesting phenomena are identified and physically explained.
Guided waves on 2D periodic structures and their relation to planar photonic band gap structures
(2000-05-01)
Hwang, RB
;
Peng, ST
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
We present here a study on the propagation characteristics of two-dimensional periodic structures. The method of mode matching is employ cd to formulate the boundary-value problem in an exact fashion, and a perturbation analysis is carried out to explain the wave phonomena associated with photonic band gap structures. The dispersion curves of 2D periodic medium and 2D periodic impedance surface are investigated in detail.
Guiding characteristics of periodic impedance surface
(2000)
Hwang, RB
;
Peng, ST
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
In this paper, we present a systematic analysis of the dispersion characteristics of two-dimensionally periodic impedance surfaces. The method of mode matching is employed analyze the boundary-value problem rigorously in terms of the complete set of both TE- and TM- polarized plane ts aves in the uniform medium above the impedance surface. Numerical results are obtained extensively and are presented graphically in the form of phase diagram, to explain various physical effects that are peculiar to the class of structures under consideration. More importantly, the unique characteristics of slanted stopband of 2D periodic structures are investigated to develop useful criteria for practical de-sign and to identify potential applications.
Microwaves in the Asia-Pacific region
(2002-03-01)
Yamashita, E
;
Bird, TS
;
Feng, ZH
;
Bhat, B
;
Akaike, M
Infrastructure elements to produce microwave engineers and to promote microwave research and development in the Asia-Pacific region are described by active professors and researchers in this area as a multiauthor forum. The content of each description focuses mainly on the role of present-day universities, government, and industry.
Performance evaluation of a bigrating as a beam splitter
(1997-04-01)
Hwang, RB
;
Peng, ST
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
The design of a bigrating for use as a beam splitter is presented. It is based on a rigorous formulation of plane-wave scattering by a big-rating that is composed of two individual gratings oriented in different directions. Numerical results are carried out to optimize the design of a bigrating to perform 1 x 4 beam splitting in two dimensions and to examine its fabrication and operation tolerances. It is found that a bigrating can be designed to perform two functions: beam splitting and polarization purification. (C) 1997 Optical Society of America.
Plane wave scattering by crossed metal-strip gratings
(1997)
Shiao, CM
;
Peng, ST
;
電信工程研究所
;
Institute of Communications Engineering
The plane-wave scattering by two crossed metal-strip gratings is formulated as a three-dimensional boundary-value problem, taking into account the polarization couplings. It is found that a large range of crossing angle between the two gratings will meet the shielding requirement in practice, regardless of the incident conditions.
Radiation characteristics of active frequency-scanning leaky-mode antenna arrays
(1999-07-01)
Wang, CJ
;
Jou, CF
;
Wu, JJ
;
Peng, ST
;
傳播研究所
Active frequency-tuning beam-scanning leaky-mode antenna arrays have been demonstrated in this paper. These antennas integrated one or several microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Noted that the measured scan angles of the 1x1 and 1x4 antennas were approximately 24 degrees and the scanning range of the 1x2 antenna was 20 degrees. Furthermore, reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array and the antenna efficiency increases. When comparing with the measured radiation pattern of the single element antenna, we found that the 1x2 and 1x4 antenna arrays can effectively suppress the reflected power by more than 5.5 dB and 10.5 dB, respectively, at 10.2 GHz. The power gain are more than 2 dB and 3.16 dB higher than the single element antenna with a measured EIRP of 18.67 dBm.