Browsing by Author "Shay, Wen-Tron"

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A Reduced-Size Wide Slot Antenna for Enhancing Along-Body Radio Propagation in UWB On-Body Communications
(2014-03-01)
Shay, Wen-Tron
;
Jan, Shiou-Chiau
;
Tarng, Jenn-Hwan
;
傳播研究所
;
Institute of Communication Studies
In this paper, a 6-10-GHz ultrawideband (UWB) directional reduced-sizewide slot antenna (RWSA) for on-body wireless communications is proposed and investigated. The RWSA is designed to be narrow in width and can be mounted on the side of a wireless device. When a side-mounted RWSA is worn on a body, the antenna boresight is naturally directed along the body surface, and most of the energy can be efficiently transmitted by direct or diffracted waves. Consequently, the on-body channel performance can be effectively improved. After a series of on-body channel measurements, the results show that, with the side-mounted RWSAs, the path loss is significantly improved (greater than 20 dB) compared with the results of previous studies, and the sensitivity of the channel to the human body and environment is effectively lessened. An approach to estimate the variation range of path loss in real environments is also proposed at the end of this paper.
Design Methodology and Performance Evaluation of a Tapered Cell
(2013-06-01)
Shay, Wen-Tron
;
Hong, Wei-Ping
;
Lao, Ray-Rong
;
Tarng, Jenn-Hwan
;
傳播研究所
Tapered cells are used in the calibration of electric field (E-field) probes. However, the design methodology of tapered cells has not been publicly reported in detail. This paper introduces the structure of a tapered cell and proposes a theoretical model for characteristic impedance calculation. Based on this model and developed design rules, an impedance-matched tapered cell was constructed. The measured characteristic impedances and impedance distribution along the cell show favorable agreement with the design goals, verifying the accuracy of the design methodology. The field distributions were also measured. The results prove that the cell is useful for calibrating E-field probes.
High-sensitivity optically modulated scatterer for electromagnetic-field measurement
(2007-04-01)
Lao, Ray-Rong
;
Liang, Wen-Lie
;
Shay, Wen-Tron
;
Thompson, Richard P.
;
Dudley, Richard A.
The optically modulated-scatterer (OMS) technique is developed for electromagnetic-field-distribution measurement with minimum disturbance to the field under test. In this paper, an OMS with newly designed photoconductive-switching structure is proposed. The performances of the new OMS are evaluated with a monostatic-field-measurement system. Measurement results show that an improvement of 6 to 8 dB in sensitivity is achieved compared to previous OMS devices. The developed OMS was used in an electromagnetic-field-distribution mapping system to measure the field distribution in a cubic phantom radiated by a mobile phone. The results show the suitability of this OMS for specific-absorption-rate measurement application.
Optically Modulated Scatterer Technique for Radiation Pattern Measurement of Small Antennas and RFID Tags
(2009)
Lao, Ray-Rong
;
Shay, Wen-Tron
;
Hsu, Jimmy C.
;
Tarng, Jenn-Hwan
;
電信工程研究所
The optically modulated scatterer (OMS) technique is developed for the electromagnetic field distribution measurement with minimum disturbance to the field under test. In this letter, we present a novel method to measure the radiation pattern of unwired small dipole-like antennas such as radio frequency identification (RFID) tag antennas by OMS technique. The radiation pattern could be measured by this technique without any metallic feeding wire that would disturb the field pattern. The variation of the radiation pattern caused by the materials attached to an RFID tag antenna could also be evaluated with this technique.
Wide Slot Antennas for UWB On-Body Communications
(2014-01-01)
Shay, Wen-Tron
;
Chen, Keng-Hsien
;
Tarng, Jenn-Hwan
;
傳播研究所
;
Institute of Communication Studies
In this paper, two modified ultra-wideband (UWB) wide slot antennas (WSAs) designed for antenna diversity in on-body communications are proposed. One antenna is a dual-polarization WSA (DPWSA) for polarization diversity. The other is a reduced-size WSA (RWSA), which is designed to be narrow in width and can be mounted on the side of a wireless device. Pattern diversity can be achieved by using two or more side-mounted RWSAs oriented in different directions. Both DPWSA and RWSA have broad impedance bandwidths and do not substantially increase the size of the original antenna or wireless device. The proposed diversity antennas can be used to mitigate the fading effects in on-body communications.