Browsing by Author "Shiao, Yu-Shao Jerry"

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Cryogenic analog-to-digital converters using spread spectrum technology for coherent receivers
(2012-01-01)
Shiao, Yu-Shao Jerry
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Chiueh, Tzihong
;
Hu, Robert
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
We propose analog-to-digital converters (ADCs) using spread spectrum technology in cryogenic receivers or at warm room temperature for coherent receiver backend systems. As receiver signals are processed and stored digitally, ADCs play a critical role in backend read-out systems. To minimize signal distortion, the down-converted signals should be digitized without further transportation. However, digitizing the signals in or near receivers may cause radio frequency interference. We suggest that spread spectrum technology can reduce the interference significantly. Moreover, cryogenic ADCs at regulated temperature in receiver dewars may also increase the bandwidth usage and simplify the backend digital signal process with fewer temperature-dependant components. While industrial semiconductor technology continuously reduces transistor power consumption, low power high speed cryogenic ADCs may become a better solution for coherent receivers. To examine the performance of cooled ADCs, first, we design 4 bit 65 nm and 40 nm CMOS ADCs specifically at 10 K temperature, which commonly is the second stage temperature in dewars. While the development of 65 nm and 40 nm CMOS ADCs are still on-going, we estimate the ENOB is 2.4 at 10 GSPS, corresponding to the correlation efficiency, 0.87. The power consumption is less than 20 mW.
DC and high-frequency characteristics of trigate polycrystalline-silicon thin-film transistors with different layout geometries
(2019-04-01)
Chen, Bo-Yuan
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Chen, Kun-Ming
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Shiao, Yu-Shao Jerry
;
Lin, Chuang-Ju
;
Huang, Guo-Wei
In this paper, we present the dc and high-frequency characteristics of trigate polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) for RF applications. Trigate TFTs were fabricated using a 3D-IC process and designed with a multi-finger gate and multi-channel configuration. To obtain an optimal device design guideline, different source/drain (S/D) extension dimensions and channel layouts are investigated. We find that devices with a shorter or wider extension have higher cutoff frequencies (f(T)) and maximum oscillation frequencies (f(max)) owing to their lower S/D resistances. In addition, the high-frequency performance can be further improved by adopting the tapered channel structure, where the channel width increases gradually from the source to the drain. For the optimal device designs, the values of f(T) and f(max) are around 25 GHz and 30 GHz, respectively. The high f(T) and f(m)(ax) as well as excellent gate controllability in our devices indicate the trigate poly-Si TFT could be a suitable candidate for low-cost RFIC applications. (C) 2019 The Japan Society of Applied Physics