Browsing by Author "Yeh, Chun-Yu"

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A Hardware-Scalable DSP Architecture for Beam Selection in mm-Wave MU-MIMO Systems
(2018-11-01)
Yeh, Chun-Yu
;
Chu, Ting-Chung
;
Chen, Chiao-En
;
Yang, Chia-Hsiang
;
電子工程學系及電子研究所
Millimeter-wave (mm-Wave) communication, operating from 30- to 300-GHz bands with wider available spectrum, has now emerged as a promising solution for future wireless systems. To reduce the hardware complexity of mm-Wave transceivers, beam-selection techniques combined with beamspace multiple-input multiple-output (MIMO) communications have been proposed in the literature. In such a system, beam selection is performed to exploit the near-sparse nature in the mm-Wave channel and, hence, is crucial to the system performance. This paper presents the world's first digital signal processing (DSP) architecture design for beam selection operation in an mm-Wave multi-user MIMO system. A computationally efficient beam-selection algorithm is first presented. Based on the proposed algorithm, a hardware-scalable beam selection processor is implemented using coordinate rotation digital computers arithmetic. To establish the validity of the concept, the proposed processor is implemented in a 40-nm CMOS technology, integrating 360k logic gates in an area of 0.5625 mm(2), while dissipating 44 mW at 266 MHz in an MU-MIMO system with 16 beams and 8 users.
Field emission properties of CNT-ZnO composite materials
(2009-02-01)
Huang, Chien-Sheng
;
Yeh, Chun-Yu
;
Chang, Yung-Huang
;
Hsieh, Yi-Min
;
Ku, Chien-Yeh
CNT-ZnO composite materials were successfully grown by thermal chemical vapor deposition (thermal CVD). First, Multiwalled Carbon nanotubes were synthesized in the temperature range of 500-700 degrees C. After coating Au nanoparticles on such grown CNTs, ZnO nanowires were synthesized via Zn evaporation method at 500 degrees C. SEM images showed that these CNT-ZnO composites were spinous, and XRD analyses showed that the spinal ZnO were crystalline. The turn-on field of CNT-ZnO composite materials with 500 degrees C growth temperature of underlying CNTs was 3.72 V/mu m, which was 5.58 V/mu m for CNTs grown at 500 degrees C. It was also found that the higher temperature (<550 degrees C) the underlying CNTs were grown at, the better field emission properties CNT-ZnO composite materials have. The WIG ratio from Raman spectroscopy of CNTs decreased as the growth temperature of CNTs increased. The graphitization of underlying CNTs played an important role in the Field emission of CNT-ZnO composite materials. (c) 2008 Elsevier B.V. All rights reserved.