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ABSTRACT: Recent years, many types of planar antennas that utilize the leaky-wave property have been investigated. Broad frequency band, higher antenna gain, frequency-scanning property, and easy to fabricate are the advantages of the planar leaky-wave antennas. In this paper, we analyze the surface-wave effect between two microstrip lines which is excited by the leaky modes and measure the relative power in the substrate to verify the result
Antennas and Propagation Society International Symposium, 2005 IEEE; 02/2005
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ABSTRACT: The paper describes the design of a 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 by ground planes provides an optimal design of radiators and other devices 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 compared to a patch-array for high gain design can simplify the complexity of the feeding layout. Versatile designs combining the merits of multilayer technology offer simplicity and efficient design for practical wireless applications.
IEEE Transactions on Antennas and Propagation 10/2003; · 2.15 Impact Factor
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ABSTRACT: 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≤2 from dc to 18.6 GHz and that of the back-to-back feeding structures has a VSWR≤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≤2 exceeds 2.3:1.
IEEE Transactions on Antennas and Propagation 09/2003; · 2.15 Impact Factor
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Tai-Lee Chen
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ABSTRACT: A multi-band printed sleeve dipole is developed by using different strip pairs to compose various frequency resonances. The measured results of an example implemented for dual-band wireless LAN reveals its multi-band characteristic. The dipole-like radiation pattern and its compact dimension show that the design can satisfy the requirements of general communication.
Electronics Letters 02/2003; · 0.96 Impact Factor
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ABSTRACT: 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
IEEE Transactions on Antennas and Propagation 07/2001; · 2.15 Impact Factor
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ABSTRACT: A dual-beam microstrip antenna, which employs the microstrip
second higher order leaky mode, is demonstrated in the paper. Using the
aperture-coupling technique, properly arranging narrow slots on the
ground plane where the vertical electric fields are small can excite the
higher order mode. Experiment results reveal that the radiation
frequency band coincides with the leaky band predicted by the spectral
domain analysis
Microwave Conference, 2001. APMC 2001. 2001 Asia-Pacific; 02/2001
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ABSTRACT: 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
Microwave Symposium Digest. 2000 IEEE MTT-S International; 02/2000
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ABSTRACT: 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 patterns
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
Electronics Letters 02/1999; · 0.96 Impact Factor
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ABSTRACT: A leaky-mode S-parameter extraction technique is proposed in this
paper. The proposed method can be employed in a numerical way or an
experimental way. By properly arranging two circuits under test, the
leaky-mode S-parameter can be de-embedded from the transmission line
theory. Numerically, this method can avoid the problem of having to deal
with a large-circuit-size structure when designing a leaky-wave antenna.
The propagation constants of the leaky modes calculated by the full-wave
spectral domain approach, and the experimental results of an
aperture-coupled leaky-wave antenna are used to confirm the parameters
extracted by this proposed technique. They all show good agreement. With
appropriate modifications, the method can also be extended to extract
and define the characteristic impedance of a leaky-wave antenna
Microwave Symposium Digest, 1999 IEEE MTT-S International; 02/1999
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ABSTRACT: 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
Electronics Letters 08/1998; · 0.96 Impact Factor
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ABSTRACT: Mode-coupling phenomena of the even modes on a microstrip line are
presented in this paper. These phenomena occur when the dispersion curve
of the microstrip line leaky dominant mode is close to those of the
conventional microstrip line dominant mode or the microstrip line higher
order modes. Interesting mode-coupling and mode evolution patterns are
observed. Current distributions of the modes near the mode-coupling
region are also shown. The ways to control the coupling region by the
geometric parameters and to avoid the excitation of the microstrip leaky
dominant mode in designing a leaky-wave antenna are discussed based on
these mode patterns
Microwave Symposium Digest, 1998 IEEE MTT-S International; 07/1998
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ABSTRACT: 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
Antennas and Propagation Society International Symposium, 1997. IEEE., 1997 Digest; 08/1997
