Browsing by Author "Lee, Wei-Che"

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A Millimeter Wave Digital CMOS Baseband Transceiver for Wireless LAN Applications
(2019-01-01)
Chiu, Kang-Lun
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Chan, Hsun-Wei
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Lee, Wei-Che
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Wu, Chang-Ting
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Lopez, Henry
In this paper, we introduce a 10 Gbps digital baseband transceiver with IV supply voltage, 16-QAM, 3/4 code rate single carrier mode using 28 nm CMOS process to do the implementation. In millimeter wave communications, well-defined standard, IEEE 802.11ad is referenced for our system design and simulation. We target at modified chip rate 2.5 GHz with 4 times parallelism hardware at clock rate 625 MHz. The overall transceiver architecture design with hardware implementation considerations will be proposed. With the smart shared memory allocation, we can reduce 31% of the total amount. According to the referenced specifications, we achieve the required bit error rate 3 x 10(-7) before SNR 18.5 dB. After the system algorithm design, we implement the hardware with the core area 2.92 mm(2) with measured power 1.8 Watt for baseband transceiver chip. The performance of energ,y per bit is 0.023 nJ and 0.211 nJ per hit 6w Tx and Rx, including ADC/DAC.
A Pseudo MMSE Linear Equalizer for 60GHz Single Carrier Baseband Receiver
(2017-01-01)
Chan, Hsun-Wei
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Wu, Chang-Ting
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Jen, Chih-Wei
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Liu, Chun-Yi
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Lee, Wei-Che
In this paper, a pseudo minimum mean square error (P-MMSE) frequency domain equalizer (FDE) is proposed to combat deep fading channel for single carrier (SC) modulation under IEEE 802.11ad and IEEE 802.15.3c standard. This FDE has resistance like MMSE to deep fading channel and maintain low complexity like zero-forcing (ZF) equalizer. In order to calculate bit error rate (BER) performance, the proposed P-MMSE integrating with our previous dual-mode baseband receiver [1] to do simulation. P-MMSE FDE can provide about 1dB improvement for 16QAM and 5 dB improvement for QPSK and BPSK when BER at 10(-2) in serious deep fading channel. Besides, it enhances the BER floor from 4 x 10(-3) to 10(-3) in 16-QAM. Moreover, P-MMSE FDE maintains the same complexity as ZF FDE.
Applications of p-n homojunction ZnO nanowires to one-diode one-memristor RRAM arrays
(2020-10-01)
Chen, Jui-Yuan
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Wu, Min-Ci
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Ting, Yi-Hsin
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Lee, Wei-Che
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Yeh, Ping-Hung
Nanowire (NW) structure is superior at defining the direction of device due to its one-dimension feature. In this work, the p-n ZnO NWs were successfully synthesized, and were able to vertically grow on Ta2O5 substrate. Thus, the well-performed Au/p-n ZnO NWs/Ta2O5/Au one-diode one-memoristor device was fabricated. The p-n ZnO NWs not only exhibited excellent rectifying behavior, but also played the role of oxygen storing during filaments formation. Therefore, the low-leakage device aimed to build high-density crossbar arrays which was required for accelerating the combination of 5 G with AI in near future applications. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Phosphorus-Doped p-n Homojunction ZnO Nanowires: Growth Kinetics in Liquid and Their Optoelectronic Properties
(2015-06-23)
Lee, Wei-Che
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Chen, Jul-Yuan
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Huang, Chun-Wei
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Chiu, Chung-Hua
;
Lin, Ting-Yi
For wide-ranging applications in nanoscale electronic devices, durable and reproducible p-type nanostructures are essential. In this work, simple ZnO nano-wire (NW) p-n homojunctions were grown using a two-step hydrothermal synthesis method. P2O5 served as a doping source to obtain p-type ZnO NW\'s. The morphology of the ZnO NW arrays was examined using field emission scanning electron microscopy. The high-resolution transmission electron microscopy (HRTEM) image indicated that the ZnO NW p-n homojunction is single-crystalline with a < 0001 > growth direction. The distribution of P element was analyzed using energy-dispersive spectroscopy. The dynamic growth observation was conducted using liquid in situ TEM to investigate the ZnO nucleation and growth mechanism. We divided the ZnO nanocrystal precipitation into three processes. Whether two adjacent particles grow stably or not was found to be related to the distance. Moreover, the temperature-dependent photoluminescence spectra revealed that two extra emission peaks located at 416 and 435 nm were emitted from the ZnO NW p-n homojunction, which resulted from donor-acceptor recombination. In addition, the electron transport properties confirmed the rectification behavior of the multi ZnO NW p-n homojunctions. The turn-on voltage and the current were approximately 2.8 V and 10(-4) to 10(-5) A, respectively, under forward bias. The results indicate the potential application of ZnO NW p-n homojunctions as nanoscale light-emitting diodes.