Browsing by Author "Chi, Yu-Jen"

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4-Port Quadri-Polarization Diversity Antenna with a Novel Feeding Network
(2012)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
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電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
A novel planar antenna with quadri-polarization diversity, including a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations is presented in this paper. The antenna comprises two square patch resonators and a feeding network with 4 input ports. Antenna polarization diversity can be achieved by selecting different inputs, which can generates right-handed circular polarization, left-handed circular polarization, horizontal linear polarization and vertical linear polarization. The proposed design does not need PIN diodes and DC biasing circuits, which makes it suitable to be used in higher frequency applications where lump elements are difficult to be utilized. This novel antenna provides potential polarization diversity features for wireless local area networks and multiple-input multiple-output systems. Details of the antenna design are shown, and the measurement and simulation results are also provided to validate the proposed idea.
60-GHz Polarization-Adjustable Antenna Arrays
(2015-07-01)
Chi, Yu-Jen
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Chen, Fu-Chiarng
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電機工程學系
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Department of Electrical and Computer Engineering
This paper proposes 2 x 2 and 4 x 4 polarization-adjustable millimeter-wave antenna arrays. The antennas were designed to function at 60 GHz and are planar and vialess. The proposed antenna designs contain two input ports; if the input phases and magnitudes of the two input ports can be controlled, enabling the proposed antenna to generate six types of polarization: right-handed circular polarization, left-handed circular polarization, and linear polarization along the phi = 0 degrees, phi = 45 degrees, phi = 90 degrees, and phi = 135 degrees axes. The achieved antenna gain of the 2 x 2 polarization diversity array was approximately 12 dBi, whereas that of the 4 x 4 array was 16 dBi. Prototypes of both the 2 x 2 and 4 x 4 arrays were fabricated and tested. The operating mechanism and design steps are described in detail in this paper.
A Novel Planar Antenna for Wireless Body Area Network
(2012)
Chi, Yu-Jen
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Chen, Fu-Chiarng
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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 novel planar antenna for wireless medical telemetry service is presented. It can be placed on the human body tissue with good antenna gain. This design is via-free and the half-wavelength patch mode of the antenna can be excited with a special feeding scheme. For different applications, the antenna can be used as a stand-alone antenna when it is fed by a coaxial cable, or to be integrated with a single chip sensor where the chip can be placed at the center of the antenna. Antenna parameters such as return loss and radiation patterns are also evaluated to validate the proposed design. Its characteristics of vialess, compact, and planar makes it a good candidate for wireless body area network applications.
A novel quadri-polarization-agile microstrip antenna with polarization synthesizing feeding network
(2016-03)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper proposes planar antennas with quadri-polarization diversity using a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations (CP). A novel feeding network with four input ports and four output ports is presented, allowing antenna polarization diversity by selecting different input ports, which can generate right-handed CP, left-handed CP, horizontal linear polarization, and vertical linear polarization. The first design uses two square patch resonators to synthesize the four polarizations; the second design comprises four circularly polarized patches to synthesize the four polarizations with an improved axial-ratio (the ratio of orthogonal components of an E-field) bandwidth. The proposed designs do not require for embedding PIN diodes and DC-biasing circuits, making them suitable for use in higher-frequency applications where using lump elements would be difficult. The novel antennas provide potential polarization diversity features which can be used for many applications. Details of the antenna design are shown, and the measurement and simulation results are also provided to validate the proposed concept.
Compact Printed Hepta-Band Monopole Antenna for Mobile Devices
(2010-01-01)
Chi, Yu-Jen
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Chen, Fu-Chiarng
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電機學院
;
電機工程學系
;
College of Electrical and Computer Engineering
A novel compact internal hepta-band planar monopole antenna for mobile devices is presented. The antenna element occupy 35.5 mm x 15.5 mm and is installed on a small ground plane which is only 35.5 mm x 60 mm Multi-resonant operation is achieved by one radiator which is comprised of two branches and a floating coupled element on the back side of the substrate. The achieved bandwidth of the proposed antenna covers nine wireless standards such as GSM, GPS, DCS, PCS, UMTS, Bluetooth, WLAN, WiMAX 2.5 GHz and WiMAX 3.5 GHz. Antenna parameters are presented to validate the proposed antenna. Low profile design is very suitable for multiband mobile communication systems.
CRLH Leaky Wave Antenna Based on ACPS Technology With 180 degrees Horizontal Plane Scanning Capability
(2013-02-01)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This study presents a novel composite right/left-handed (CRLH) leaky wave antenna (LWA) with horizontal plane scanning capability. This LWA consists of 10 CRLH unit cells and coplanar waveguide to coplanar stripline transitions. The proposed balanced CRLH unit cell is based on an asymmetric coplanar stripline structure (ACPS). The parameters of the CRLH unit cell can be determined analytically, enabling easy modification for any other frequency band. Because of its planar and horizontal plane scanning property, the proposed design can also be extended to a sector-shaped multisection LWA, achieving a scanning range of more than 180 in the horizontal plane. By varying the operating frequency, the CRLH leaky wave antenna shows the continuously beam-scanning property from backward to forward in the horizontal plane. A 10-cell prototype exhibits the beam-scanning capability in the horizontal plane, and a 20-cell multisection sector-shaped LWA confirms the approach of designing the wide-range beam-scanning LWA. Experimental results show that the proposed design is in good agreement with the simulation. The planar and low-profile characteristics of the novel CRLH LWA make it suitable for integration with other microwave circuits, and can be applied to applications that require a wider beam-scanning range.
Empirical MIMO Capacity of a 2x2 Dual-Polarized Planar Antenna Array in Indoor 60 GHz Channels
(2013)
Chiu, Lin-Kai
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Chiang, Ming-Chen
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Chiang, Pei-Li
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Chi, Yu-Jen
;
Wu, Sau-Hsuan
The channel capacity of a multiple input multiple output (MIMO) system that uses a hybrid beamforming (HBF) mechanism for a 2x2 dual-polarized (DP) planar antenna array (PAA) is studied in this work for indoor 60 GHz channels. On one hand, the DP-PAA can resolve the receiving dead zone problem often seen in single-polarized PAA. On the other hand, the HBF architecture allows us to explore the advantages of spatial multiplexing or beamforming, or even both, in order to overcome the severe power loss problems often encountered from blocking or reflections in indoor 60 GHz radio propagations. Simulation results show that different architectures have advantages at different transmission power. In typical operating conditions of indoor 60 GHz radio, directivity offered by beamforming provides a higher capacity than does the spatial multiplexing provided by multiple baseband processing modules.
Novel CRLH Leaky Wave Antenna with Horizontal Scanning Property
(2011)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
;
電機學院
;
電機工程學系
;
College of Electrical and Computer Engineering
A novel composite right/left-handed (CRLH) leaky-wave antenna (LWA) with horizontal scanning capability is presented. It consists of 10 CRLH unit cells and coplanar waveguide (CPW) to coplanar strpline (CPS) feeding schemes. The proposed balanced CRLH unit cell is designed based on coplanar stripline structure. Dimensions of the CRLH unit cell could be determined analytically, which makes it easily to be modified to operate at any other frequency band. By varying the operating frequency, the CRLH leaky wave antenna reveals the continuously beam scanning capability from backward to forward in the azimuth plane, which achieves about 135 scanning range of angels. The simulated return loss as well as far-field radiation patterns were also provided to verify its beam-scanning property in horizontal plane. Planar and low profile characteristics of the novel CRLH LWA make it suitable to be integrated with other microwave circuits.
On-Body Adhesive-Bandage-Like Antenna for Wireless Medical Telemetry Service
(2014-05-01)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper presents a novel planar, via-free, printed antenna for wireless medical telemetry service (WMTS). The antenna structure is simple and looks like an adhesive bandage, and can be placed on human tissue. Depending on the application, the antenna can be used as a standalone antenna when it is fed by a coaxial cable, or it can be integrated with a single-chip sensor, with the chip placed in the center. Antenna parameters, such as reflection coefficients, radiation patterns, radiation efficiency, and the specific absorption rate, were evaluated in various scenarios to validate the proposed design. The measured radiation efficiency of the proposed adhesive-bandage-like antenna was 89.5% in free space and 44.7% when mounted on tissue-equivalent phantom. The antenna also retained its broad side radiation characteristics when it was bent at 90 degrees. The proposed antenna is a favorable candidate for use in wireless body area networks (WBANs). This paper presents the detailed design considerations of the proposed antenna.
Planar Four-Port Quadri-Polarization Slot Antenna for Millimeter Wave Application
(2014-01-01)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
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電機工程學系
;
Department of Electrical and Computer Engineering
This paper presents a planar, vialess printed slot dipole antenna with polarization switchable characteristic. The proposed design comprises four input ports, and each input ports corresponds to different polarizations such as horizontal polarization, vertical polarization, right-handed circular polarization, and left-handed circular polarization. Because lumped diodes are not available in millimeter wave frequency band, polarization diversity antenna designs using diodes are not applicable. The proposed design does not require PIN diodes and DC biasing circuits, which makes it suitable to be used at higher frequency band. It can be easily printed on a circuit board and integrated with RF circuits using flip chip. The low cost and easy implement characteristic enables polarization agile antenna design for millimeter wave frequency band.
Quadri-Polarization Diversity Antenna with Extended Axial Ratio Bandwidth
(2013)
Chi, Yu-Jen
;
Chen, Fu-Chiarng
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper presents a four-port planar antenna with quadri-polarization diversity with a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations. The design comprises four circularly polarized patches to synthesize the four polarizations with an extended axial-ratio bandwidth. Polarizations of the antenna can be changed be selecting different inputs.