| 1. |
- Wang, Dian-Zheng, et al.
(författare)
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Cracking Behavior in Additively Manufactured Pure Tungsten
- 2019
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Ingår i: Acta Metallurgica Sinica (English Letters). - : Springer Science and Business Media LLC. - 1006-7191 .- 2194-1289. ; 32:1, s. 127-135
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Tidskriftsartikel (refereegranskat)abstract
- In this study, near fully dense (96.5%) pure tungsten bulks were additively manufactured and the cracking behavior was investigated. A crack network with a spacing of similar to 100m was observed in the fabricated bulks. It was observed that the laser scanning strategy, which could tailor the microstructure, affected the crack distribution pattern in fabricated tungsten. The calculated surface temperature difference (7300K) was much higher than the cracking criterion (800K) of tungsten, indicating that cracking is almost inevitable in laser additive manufacturing of tungsten. It could be concluded that crack network formed because the cracks emerged in every laser molten track and then interconnected in the layer-by-layer building process.
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| 2. |
- Wang, Peng, et al.
(författare)
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Low Noise Amplifier Architecture Analysis for OFDM-UWB System in 0.18 um CMOS
- 2008
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Ingår i: 26th Norchip Conference, Norchip. - 9781424424931 ; , s. 184-189
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes architectures of the low noise amplifier (LNA) for orthogonal-frequency-division-multiplexing ultra-wideband (OFDM-UWB) application. Until now, most UWB LNA implementations are focusing how to realize a single LNA covering the whole frequency band. In this work three popular wide-band LNA architectures are compared to a proposed parallel LNA architecture in which different amplifiers cover different frequency bands. Our study reveals that by reusing the source degenerated inductor between the different frequency bands, the parallel LNA architecture can achieve better performance than the single wide-band LNA (S11<-10 dB, voltage gain >15 dB, NF >4.5 dB, power consumption <10 mW) at the expense of a slightly increased circuit area.
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| 3. |
- Wang, Peng, et al.
(författare)
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Low Noise Amplifier Architecture Analysis for UWB System
- 2008
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Ingår i: 2008 INTERNATIONAL SYMPOSIUM ON SYSTEM-ON-CHIP, PROCEEDINGS. - NEW YORK : IEEE. ; , s. 53-56
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes the architecture of wideband low noise amplifier (LNA) for multi-band orthogonal frequency division multiplexing modulation (MB-OFDM) ultra-wideband (UWB) system. Noise matching and input impedance matching are compared among different LNA architectures. Power consumption and area for different kinds of LNA architectures are also compared through the figure of merit (FOM).
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| 4. |
- Wang, Peng, et al.
(författare)
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PER Performance Enhancement through Antenna And Transceiver Co-Design for Multi-band OFDM UWB Communication
- 2008
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Ingår i: 2008 INTERNATIONAL SYMPOSIUM ON SYSTEM-ON-CHIP, PROCEEDINGS. - NEW YORK : IEEE. - 9781424425419 ; , s. 142-146
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the packet error rate (PER) performance enhancement through the antenna and the transceiver co-design for MB-OFDM UWB system. Five different UWB antennas, covering the whole UWB spectrum, are selected for study. Through the link-margin analysis and PER performance simulation, radio transceiver design specifications are optimized according to different antennas' performance at different band groups. Transmitter pre-distortion and receiver equalization are applied at the front-end of the transceiver to co-design with the antenna, which further enhance PER performance. Our study reveals that, antenna is an important part of radio transceiver which has to be considered in advance during the chip design [1], particularly in the ultra-wide band radio system. Through the antenna and radio front-end co-design, not only could PER performance be enhanced, but also could design parameters be relaxed for the power amplifier (PA) and the low noise amplifier (LNA), particularly for higher band groups.
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