Browsing by Author "Hu, CC"

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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 Gunn-diode active leaky-wave frequency scanning antenna
(1998-01-01)
Lee, SH
;
Jou, CK
;
Lee, CP
;
Hu, CC
;
Wu, JJ
A frequency tunable active leaky-wave scanning antenna using Gunn-diode voltage control oscillator (VCO) as source is developed. The frequency tuning controlled by changing either the varactor diode de bias or the Gunn diode de bias is demonstrated. The measured scanning angle of active antenna is close to 15 degree as the Gunn VCO frequency tuned from 12.58GHz to 12.98GHz. To excite the first higher order mode of the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the middle line of the microstrip leaky wave antenna. This is a prototype of frequency scanning antenna using two terminal device, which can be easily scaled up to millimeter wave frequency region.
A two-dimensional beam-scanning linear active leaky-wave antenna array
(1999-03-01)
Hu, CC
;
Jou, CF
;
Wu, JJ
;
傳播研究所
;
Institute of Communication Studies
This letter presents a new technique fur electronic two-dimensional beam scanning using a phase-shifterless linear active leaky-wave antenna array. The varactor-tuned voltage-controlled oscillators (VCO's) and coupling network are implemented in this array. The measured pattern of this 4 x 1 leaky-wave antenna array shows that the main beam can be continuously scanned from 68 degrees to 40 degrees in elevation as the frequency varied from 8.24 to 9.15 GHz. By tuning the free-running frequencies of the end elements, the main beam can be continuously scanned from -26 degrees to +10 degrees in azimuth, A maximum ERP of 667 mW is measured at 8.9 GHz for this active antenna array.
Active aperture-coupled leaky-wave antenna
(1998-11-12)
Kao, NA
;
Hu, CC
;
Wu, JJ
;
Jou, CF
;
傳播研究所
An active aperture-coupled leaky-wave antenna which is integrated with a varactor-tuned high electron mobility transistor voltage-controlled oscillator (HEMT VCO) is presented. To excite the first higher mode of the microstrip, the aperture-coupled structure is used and a sequence of covered wire is added at the centre of this antenna to suppress the dominant mode. The measured H-plane main beam can be continuously scanned 10 degrees as the HEMT VCO frequency is varied from 9.05 to 9.5GHz. This feeding structure is very suitable for active phase antenna array applications.
Active feedback microstrip leaky wave antenna-synthesiser design with suppressed back lobe radiation
(1999-04-01)
Shih, YC
;
Chen, SK
;
Hu, CC
;
Jou, CF
;
傳播研究所
The design of an active leaky-wave antenna which integrates the antenna with a feedback synthesiser is introduced. The measurement result shows that the antenna has very low back lobe radiation compared with that of traditional single-terminal feeding leaky-wave antennas. Single frequency measurement shows that the radiated power differmce between the main beam and back lobe is >15 dB at 8.2 GHz For the designed feedback synthesiser antenna, the measured radiated power difference between the main beam and back lobe is >15dB at 9.25 GHz, and the scanning angle is similar to 5 degrees as the synthesiser frequency sweeps from 9.25 to 9.37 GHz.
An active frequency-tuned beam-scanning leaky-wave antenna
(1998-01-01)
Hu, CC
;
Wu, JJ
;
Jou, CF
;
交大名義發表
;
傳播研究所
A frequency-tuned beam-scanning antenna is developed, which integrated a microstrip leaky-wave antenna with a varactor-tuned HEMT VCO as the source. The microstrip leaky-wave antenna is operated in the first higher mode. To excite the first higher mode, microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the center of the microstrip leaky-wave antenna. The HEMT oscillator frequency is controlled by tuning the varactor dc bias, and the beam scanning is demonstrated. The measured scanning angle agrees well with the prediction; it is close to 30 degrees as the VCO frequency is tuned from 8.06 to 9 GHz. (C) 1998 John Wiley & Sons, Inc.
An aperture-coupled linear leaky-wave antenna array with 2-D dual-beam scanning capability
(2000-04-05)
Hu, CC
;
Wu, JJ
;
Jou, CF
;
傳播研究所
;
Institute of Communication Studies
An X-band four-element linear microstrip leaky-wave antenna (LWA) array wit a dual-beam radiation pattern and two-dimensional scanning capability is developed. The measured half-power beamwidths of the H-plane and quasi-E-plane radiation patterns are less than 30 degrees. By tuning the dc bias of the varactor phase shifter between the antenna elements, the main beam can be scanned in the azimuth plane from -13 degrees to +13 degrees off broadside. In the elevation plane, the beam-scanning angle is close to 20 degrees as the operating frequency is tuned form 11.58 to 12.5 GHz. (C) 2000 John Wiley & Sons, Inc.
An aperture-coupled linear microstrip leaky-wave antenna array with two-dimensional dual-beam scanning capability
(2000-06-01)
Hu, CC
;
Jou, CF
;
Wu, JJ
;
傳播研究所
;
Institute of Communication Studies
This paper describes an X-band 4 x 1 aperture-coupled series-fed electronically steerable microstrip leaky-wave antenna (LWA) array design, which has dual-beam radiation pattern and two-dimensional (2-D) beam-scanning capability. The LWA array is operated in the first higher order mode and excited by center-fed aperture coupled for dual-beam operation. The varactor-tuned phase shifters are placed between the antenna elements. The measured half-power beamwidth of the H-plane and quasi-E-plane radiation patterns are less than 30 degrees. By tuning the reverse de bias of the varactor diodes, the main beam can be scanned in azimuth plane from -13 degrees to +13 degrees off broadside. In the elevation plane, the beam-scanning angle is close to 20 degrees as the operating frequency tuned from 11.58-12.5 GHz. Taking into account each phase-shifter insertion loss and phase progression, the measured results compared closely with the theoretical prediction, The proposed antenna array is suitable for wireless communication and collision warning radar systems.
An asymmetric feeding X-band active frequency-scanning leaky-wave antenna
(1997-09-01)
Hu, CC
;
Wu, JJ
;
Jou, CF
;
交大名義發表
;
傳播研究所
An asymmetric feeding X-band active leaky-wave antennas is developed, to excite the first high order mode of the microstrip leaky wave antenna. One is the asymmetric feeding leaky-wave antenna which integrated with a HEMT oscillator, and the other is the frequency-tuned leaky-wave antenna which integrated with a varactor-tuned HEMT VCO. The microstrip leaky-wave antenna is operated in the first higher mode. To excite the first higher mode, the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the center of the microstrip leaky wave antenna. The design of these active leaky-wave antennas is discussed and the beam scanning phenomena of the antenna is presented. The HEMT oscillator frequency is controlled by tuning the varactor DC bias and the beam scanning is demonstrated. The measured scanning angle agree with prediction, it is close to 30 degrees as the VCO frequency tuned from 8.06 GHz to 9GHz.
An asymmetric feeding X-band active frequency-scanning leaky-wave antenna
(1997-09-01)
Hu, CC
;
Wu, JJ
;
Jou, CF
;
電信工程研究所
;
Institute of Communications Engineering
An asymmetric feeding X-band active leaky-wave antennas is developed, to excite the first high order mode of the microstrip leaky wave antenna. One is the asymmetric feeding leaky-wave antenna which integrated with a HEMT oscillator, and the other is the frequency-tuned leaky-wave antenna which integrated with a varactor-tuned HEMT VCO. The microstrip leaky-wave antenna is operated in the first higher mode. To excite the first higher mode, the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the center of the microstrip leaky wave antenna. The design of these active leaky-wave antennas is discussed and the beam scanning phenomena of the antenna is presented. The HEMT oscillator frequency is controlled by tuning the varactor DC bias and the beam scanning is demonstrated. The measured scanning angle agree with prediction, it is close to 30 degrees as the VCO frequency tuned from 8.06 GHz to 9GHz.
An integrated logistics operational model for green-supply chain management
(2005-07-01)
Sheu, JB
;
Chou, YH
;
Hu, CC
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper presents an optimization-based model to deal with integrated logistics operational problems of green-supply chain management (G-SCM). In the proposed methodology, a linear multi-objective programming model is formulated that systematically optimizes the operations of both integrated logistics and corresponding used-product reverse logistics in a given green-supply chain. Factors such as the used-product return ratio and corresponding subsidies from governmental organizations for reverse logistics are considered in the model formulation. Results of numerical studies indicate that using the proposed model, the chain-based aggregate net profits can be improved by 21.1%, compared to the existing operational performance in the particular case studied. © 2004 Elsevier Ltd. All rights reserved.
An integrated logistics operational model for green-supply chain management
(2005-07-01)
Sheu, JB
;
Chou, YH
;
Hu, CC
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper presents an optimization-based model to deal with integrated logistics operational problems of green-supply chain management (G-SCM). In the proposed methodology, a linear multi-objective programming model is formulated that systematically optimizes the operations of both integrated logistics and corresponding used-product reverse logistics in a given green-supply chain. Factors such as the used-product return ratio and corresponding subsidies from governmental organizations for reverse logistics are considered in the model formulation. Results of numerical studies indicate that using the proposed model, the chain-based aggregate net profits can be improved by 21.1%, compared to the existing operational performance in the particular case studied. © 2004 Elsevier Ltd. All rights reserved.
Asymmetric feeding active leaky-wave antenna arrays
(1998-05-01)
Wang, CJ
;
Wu, JJ
;
Hu, CC
;
Jou, CF
;
傳播研究所
The active leaky-wave antenna arrays have been demonstrated, which integrate several microstrip leaky-wave antenna elements with a single HEMT oscillator as an active source at 10.2 GHz. To excite the first higher order mode, the leaky-wave antenna is fed asymmetrically. The reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array. When comparing with the measured radiation pattern of the single-element antenna, we found that 1 x 2 and 1 x 4 antenna arrays can effectively suppress the reflected power by more than 5.5 and 10.5 dB, respectively. Furthermore, the power gains are more than 2 and 3.16 dB higher than the single-element antenna with a measured EIRP of 18.67 dBm. (C) 1998 John Wiley & Sons, Inc.
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.
Coplanar waveguide to coplanar strips-fed active leaky-wave antenna
(1998-12-05)
Hu, CC
;
Jou, CF
;
Wang, CJ
;
Lee, SH
;
Wu, JJ
A new active coplanar waveguide (CPW) to coplanar ships (CPS)-fed microstrip leaky-wave antenna is developed, which is integrated with a Gunn diode as an 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 a maximum EIRP of 20.4 dBm at 9.759 GHz. The Gunn oscillator frequency is controlled by tuning the Gunn de 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 is tuned from 9.84 to 9.61 GHz. The coplanar structure allows easy integration of many solid-state devices. It is suitable for monolithic power combining ann millimeter-wave applications. (C) 1998 John Wiley & Sons, Inc.
Coplanar waveguide to coplanar strips-fed active leaky-wave antenna
(1998-12-05)
Hu, CC
;
Jou, CF
;
Wang, CJ
;
Lee, SH
;
Wu, JJ
A new active coplanar waveguide (CPW) to coplanar ships (CPS)-fed microstrip leaky-wave antenna is developed, which is integrated with a Gunn diode as an 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 a maximum EIRP of 20.4 dBm at 9.759 GHz. The Gunn oscillator frequency is controlled by tuning the Gunn de 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 is tuned from 9.84 to 9.61 GHz. The coplanar structure allows easy integration of many solid-state devices. It is suitable for monolithic power combining ann millimeter-wave applications. (C) 1998 John Wiley & Sons, Inc.
Efficient deployment algorithms for ensuring coverage and connectivity of wireless sensor networks
(2005)
Wang, YC
;
Hu, CC
;
Tseng, YC
;
資訊工程學系
;
Department of Computer Science
Sensor deployment is a critical issue since it reflects the cost and detection capability of a wireless sensor network. Although lots of work has addressed this issue, most of them assume that the sensing field is an open space and there is a special relationship between the communication range and sensing range of sensors. In this work, we consider the sensing field as an arbitrary-shaped region possibly with obstacles. Besides, we allow an arbitrary relationship between the communication range and sensing range, thus eliminating the constraints of existing results. Our approach is to partition the sensing field into smaller sub-regions based on the shape of the field, and then to deploy sensors in these sub-regions. Simulation results show that our method requires fewer sensors compared to existing results.
Equivalence classes of Vogan diagrams
(2004-09-01)
Chuah, MK
;
Hu, CC
;
應用數學系
;
Department of Applied Mathematics
A Vogan diagram is a Dynkin diagram with an involution, and the vertices fixed by the involution may be painted. They represent real simple Lie algebras, and two diagrams are said to be equivalent if they represent the same Lie algebra. In this article we classify the equivalence classes of all Vogan diagrams. In doing so, we find that the underlying Dynkin diagrams have certain properties in graph painting. We show that this combinatorial property provides an easy classification for most of the simply-laced Dynkin diagrams. (C) 2004 Published by Elsevier Inc.
Experiment on an aperture-coupled leaky-wave antenna with a pencil beam
(1999-04-05)
Kao, NA
;
Hu, CC
;
Wu, JJ
;
Jou, CF
;
傳播研究所
A frequency-scanning leaky-wave antenna with an aperture-coupled feeding structure is presented. The aperture-fed structure is used to excite the microstrip first higher mode. In order in suppress the dominant mode, we add a sequence of covered wire in the center of this antenna. The measured H-plane main beam is a pencil beam, and is continuously scanned 12 degrees as the frequency varies from 9.85 to 10.27 GHz. This feeding structure is very suitable for active phase antenna array applications. (C) 1999 John Wiley & Sons, Inc.