Browsing by Author "Kitazawa, Toshihide"

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A novel dual circularly polarized microstrip antenna
(2006)
Hong, Wanchu
;
Chenq, Chin-Ting
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
電信工程研究所
In this paper, we propose a novel design of dual circularly polarized microstrip antenna of the cogwheel-like annular ring structure. The microstrip sector stubs are added periodically in the outer and inner edges of the microstrip annular ring and an additional microstrip line as a diameter is also placed across the inner circle to enhance performance of the axial ratio. When operated in TM11 mode, this cogwheel-like microstrip annular ring antenna has a relatively wider bandwidth and a relatively smaller size than those of the traditional microstrip annular ring antenna. The three-wire transmission line and branch-line hybrid is employed as the feeding network to excite the righted-handed or left-handed direction of circular polarization.
Broadband Inverted-T Leaky-wave Antennas
(2008)
Lin, Lieh-Chuan
;
Kitazawa, Toshihide
;
Lin, Yu-De
;
交大名義發表
;
National Chiao Tung University
Characterization and design of cylindrical microstrip leaky-wave antennas
(2008-07-01)
Lin, Lieh-Chuan
;
Miyagawa, Hayato
;
Kitazawa, Toshihide
;
Hwang, Ruey Bing
;
Lin, Yu-De
The spectral-domain approach is applied for the analysis and the design of the cylindrical microstrip leaky-wave antenna. The first higher-order leaky-mode is thoroughly investigated. We perform the well-known spectral-domain approach and Galerkin's method to acquire the complex propagation constants of leaky modes, which are verified with results obtained by the scattering-parameter extraction technique. Two practical antennas are designed and implemented. Measured return loss and radiation patterns show a good performance of these cylindrical antennas, compared to that of the planar ones.
Circularly Polarized Slotted Conductor-backed Coplanar Waveguide (CBCPW) Antenna Array with Sequentially Rotated Feeding Structure
(2009)
Lin, Yow-Shyan
;
Lin, Lieh-Chuan
;
Kitazawa, Toshihide
;
Lin, Yu-De
;
電信工程研究所
In this paper, circularly polarized slotted antenna arrays on conductor-backed coplanar waveguide (CBCPW) operating at Ku band are proposed. Radiating slots along the propagation direction of the parallel-plate mode in the CBCPW structure are etched to radiate into the air. By appropriately arranging the position and tilt angle for each slot, we can implement a kite-shaped linearly polarized antenna array with high gain and narrow beamwidth. Combining four linearly polarized arrays with a sequentially rotated feeding structure can produce a circularly polarized slotted CBCPW antenna arrays. Two arrangements of the sequential rotation method with the feeding phases in a 0 degrees, 90 degrees, 0 degrees, 90 degrees fashion and a 0 degrees, 90 degrees, 180 degrees, 270 degrees fashion are used. The measured gains are 24.889 dBiC for the 0 degrees, 90 degrees, 0 degrees, 90 degrees arrangement and 24.691 dBiC for the 0 degrees, 90 degrees, 180 degrees, 270 degrees arrangement, respectively. The bandwidths of the axial ratio (AR) below 3 dB are 330 MHz and 370 MHz,
Composite Sector-Beam Single-Conductor Leaky-Wave Antenna for Base-Station Applications
(2012)
Wu, Chi-Che
;
Lin, Hsueh-Chun
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
電信工程研究所
A switchable sector-beam single-conductor leaky-wave antenna array is proposed. First, we use the spectral domain approach to acquire the propagation constant of the single-conductor structure. Then we use a radiation pattern synthesis method to estimate the radiation pattern of the sectorial antenna array. Two sector-beam single-conductor leaky-wave antenna arrays with half power beamwidths (HPBWs) of 70 degrees and 90 degrees respectively are designed. Using an RF single-pole four-throw (SP4T) switch, the mainbeam of the switchable antenna array could cover the whole 360 degrees azimuth plane Besides, we use a half wavelength meandering strip to reduce the back lobe of the single-conductor leaky-wave antenna.
Electromagnetic Interference in Substrate-Integrated Waveguides Circuit and Its Suppression Technique
(2010-01-01)
Hwang, Ruey-Bing
;
Chin, Cheng-Yuan
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
Wu, Chang-Yu
As was well known, the substrate-integrated waveguide can be easily implemented and integrated with active and passive devices using the printed circuit process. Thus, the integration circuit and system based on the substrate integrated waveguide technique becomes achievable. However, in the integrated circuit environment, the close proximity between adjacent substrate-integrated waveguides may cause the electromagnetic coupling, and thus the electromagnetic interference problem arises accordingly. In this research, we demonstrate the electromagnetic coupling between two parallel substrate integrated waveguide. Moreover, the theory of Fabry-Perot resonator was employed to explain the resonance coupling between the substrate-integrated waveguides. On the other hand, a new substrate-integrated waveguide equipped with moats [1] was utilized to examine the capability of cross-talk suppression. Interestingly, we find that in comparison with the conventionally used substrate-integrated waveguide the new one can effectively suppress the electromagnetic wave coupling. Therefore, the signal integrity can be further improved in a microwave or millimeter-wave circuit or system implemented using the substrate-integrated waveguide technique.
Evaluation of Complex Permittivity of Materials with Deformed Cross-section in Coaxial Line
(2009)
Sakemoto, Yuya
;
Harada, Atsushi
;
Wakino, Kikuo
;
Lin, Yu-De
;
Kitazawa, Toshihide
A broadband measurement method is presented to evaluate the complex permittivity of a deformed sample. Theoretical basis of the method is the hybrid electromagnetic field analysis, i.e, the extended spectral domain approach combined with mode-matching method (ESDMM). The sample is required to have the rotational symmetry but may have the deformation and/or air gap between the sample and the conductor walls of coaxial line, which eases the machining accuracy of sample. The proposed evaluation method is verified by virtual experiments as well as actual measurements.
Leaky-mode propagation characteristics of slotted coaxial lines
(2007)
Lin, Lieh-Chuan
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
交大名義發表
;
National Chiao Tung University
Propagation Characteristics of Leaky Coplanar Waveguides on Cylindrical Substrates
(2007)
Lin, Lieh-Chuan
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we investigate the space-wave leaky modes of coplanar waveguides (CPW) on cylindrical substrates and analyze their propagation characteristics. The first higher order leaky mode is assumed and propagation constants of it are solved by the spectral-domain approach (SDA). The effects of outer radii, center strip widths, and slot widths, are discussed. From our numerical results, center strip widths and slot widths play similar roles in design of these structures. Besides, we find that coplanar waveguides on cylindrical substrates have the capability to be wideband antennas.
Simultaneous Determination of Complex Permittivity and Permeability of Columnar Materials With Arbitrarily Shaped Cross Section
(2009-09-01)
Miyagawa, Hayato
;
Wakino, Kikuo
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
電信工程研究所
An effective simultaneous evaluation method for the complex permittivity and permeability of lossy materials is proposed by applying it to an arbitrarily shaped cross-sectional post placed in a rectangular waveguide. We use one sample and only measure S(21) parameters for two different locations of the sample. The measurement of complex reflection parameter S(11) is not required in this evaluation method. The scheme of electromagnetic field analysis for the evaluation is based on the extended spectral-domain approach combined with the mode-matching method, which is accurate and efficient, and can be flexibly used for the iterative fitting operation for the estimation of material parameters. Sample preparation and setting is significantly easier in this method compared to conventional methods. The error caused by deviations in the setting of a sample is investigated. The estimated values for the sample material by this procedure show good agreement with the results obtained using the conventional method over the X-band.
Spectral domain approach to the scattering analysis of coaxial discontinuities
(2007-02-01)
Nakata, Takamichi
;
Yoshitake, Hiroaki
;
Wakino, Kikuo
;
Lin, Yu-De
;
Tani, Tohru
The extended version of spectral domain approach (ESDA) is applied to evaluate the scattering characteristics of discontinuities in coaxial line. Discontinuities may be in inner and/or outer conductor of coaxial line. This method secures the high accuracy by considering the singularities of fields near the conductor edge properly. The computational labor of the new method is far lighter than that of FEM, so that novel method is suitable for the time consuming iterative computation such as fitting procedure in material evaluation or optimization of antenna design.
UWB Printed Monopole Antenna with Radiation-Suppression in 5-GHz ISM Band
(2008)
Chen, Yu
;
Lin, Lieh-Chuan
;
Lin, Yu-De
;
Kitazawa, Toshihide
;
電信工程研究所