Browsing by Author "Chen, TL"

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A K-band aperture-coupled microstrip leaky-wave antenna
(1999-07-01)
Chen, TL
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
Microstrip leaky-wave antenna fed bf an aperture-coupled microstrip operating at K-band is presented. Using the aperture-coupled microstrip as a feeding structure can fully exploit the wideband characteristic of the microstrip leaky-wave antenna. The dimensions of the antenna are obtained from the calculation of the propagation characteristics. Measurement shows a bandwidth of 22% for VSWR < 2 : 1 and a peak power gain of 12 dBi at 22 GHz for one element. Four-element array is developed with a gain of 18.7 dBi and the frequency-scanning feature is exhibited. The waveguide model is verified by measuring the 3-D, radiation pattern of the microstrip leaky-wave array.
A new data-aided OFDM symbol timing synchronization algorithm based on histogram processing
(2005)
Sang, TH
;
Hsu, SY
;
Chen, TL
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new data-aided OFDM symbol timing synchronization method is developed with two goals in mind: to achieve robust performance and to reduce computational cost. It is the intuitive observation of the relationship between the symbol timing shift and the constellation rotation on each subcarrier of an OFDM symbol from which the new method is developed. A histogram-based algorithm is used to extract the timing shift information from the FFT output. Simulations are conducted to verb the effectiveness and robustness of this new algorithm. Comparison with commonly-used algorithms based on correlation is also provided.
Aperture-coupled microstrip line leaky wave antenna with broadside mainbeam
(1998-07-09)
Chen, TL
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
A microstrip first higher order leaky wave antenna (LWA), centre-fed by an aperture-coupled microstrip with a broadside mainbeam, is presented. The measured bandwidth (23% for VSWR < 2:1) is in agreement with the leaky radiation band predicted. The experimental gain patterns, compared with those of a patch antenna fed by the same type of structure, reveal the difference between these two kinds of antenna. With increasing frequency, the radiation field of the LWA spreads into the H-plane, forming a flatter broadside pattern, which can be applied to long rectangular area communication.
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.
Design of the feeding structures for the excitation of the microstrip line second higher order mode leaky-wave antenna
(1997)
Lin, YD
;
Chi, PM
;
Chen, TL
;
交大名義發表
;
傳播研究所
Two feeding structures for the excitation of the microstrip line second higher order mode as leaky-wave line sources are proposed in this paper. Since the second higher order mode of the microstrip line assumes a magnetic wall symmetry plane at the center of the strip as the dominant mode does, the feeding line adopted is coplanar waveguide (CPW). One of the feeding structures uses CPW on the same plane with the microstrip; while the other places the feeding CPW on the ground plane of the microstrip line. To suppress the excitation of the dominant mode, the slots of the feeding coplanar waveguide are placed appropriately. Experiments are conducted to exhibit the efficiency of the excitation schemes.
Dual-beam microstrip leaky-wave array excited by aperture-coupling method
(2003-09-01)
Chen, TL
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
This paper describes the design of the microstrip leaky-wave array excited by the aperture-coupling technique. The microstrip first higher order leaky mode is employed as the radiation source. Separating the radiators from other components with the ground planes provides optimal design of radiators and others so that the inherent broadband, high gain and frequency-scanning properties of the leaky-wave antenna can be exploited. Four kinds of feeding arrangements to excite dual beams are experimented in K band. Markedly reducing the required elements than patch-array for high gain design can simplify complexity of the feeding layout. Versatile designs combining the merits of multilayer technology offer simplicity and efficient design for practical wireless applications.
Excitation of the microstrip higher order leaky modes by aperture-copuling method
(2000)
Chen, TL
;
Lin, YD
;
交大名義發表
;
National Chiao Tung University
A simple method for exciting the microstrip higher order leaky modes is demonstrated in the paper. Properly arranging narrow slots on the ground plane where the vertical electric fields are small can excite these higher order modes. The experiments of excitation of the second and the third higher order leaky modes are carried out to verify the practicability. It is suitable to develop new microwave device and radiation source, such as applications in multi-beam antenna design.
MEMS SoC: observer-based coplanar gyro-free inertial measurement unit
(2005-09-01)
Chen, TL
;
Park, S
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機械工程學系
;
Department of Mechanical Engineering
This paper presents a novel design of a coplanar gyro-free inertial measurement unit (IMU) that consists of seven to nine single-axis linear accelerometers, and it can be utilized to perform the six DOF measurements for an object in motion. Unlike other gyro-fee IMUs, this design uses redundant accelerometers and state estimation techniques to facilitate the in situ and mass fabrication for the employed accelerometers. The alignment error from positioning accelerometers onto a measurement unit and the fabrication cost of an IMU can greatly be reduced. The outputs of the proposed design are three linear accelerations and three angular velocities. As compared to other gyro-free IMUs, the proposed design uses less integral operation and thus improves its sensing resolution and drifting problem. The sensing resolution of a gyro-free IMU depends on the sensing resolution of the employed accelerometers as well as the size of the measurement unit. Simulation results indicate that the sensing resolution of the proposed design is 2 degrees s(-1) for the angular velocity and 10 mu g for the linear acceleration when nine single-axis accelerometers, each with 10 mu g sensing resolution, are deployed on a 4 inch diameter disc. Also, thanks to the iterative EKF algorithm, the angle estimation error is within 10(-3) deg at 2 s.
Microstrip leaky-wave antenna fed by short-end CPW-to-slot transition
(1999-01-21)
Chen, TL
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
Single and dual-beam microstrip leaky-wave antennas fed by a short-end coplanar waveguide (CPW)-to-slot transition are presented. The radiation bands of the antennas are deduced from the leaky-wave propagation characteristics of the microstrip line first higher order leaky mode. The measured reflection coefficients of the radiation band confirm the predicted leaky band and the measured radiation paffems exhibit. the frequency-scanning feature of the leaky-wave antenna. The short-end CPW-to-slot transition feeding method simplifies the circuit layout and is more suitable for different band design than the CPW-fed microstrip first higher order leaky-wave antennas presented in the literature.
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.