Browsing by Author "Shen, I-Shing"

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A Colpitts Current-Reused QVCO Based on Capacitor Coupling
(2011)
Lai, Hsing-Han
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Shen, I-Shing
;
Jou, Christina F.
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電信工程研究所
;
Institute of Communications Engineering
This paper presents a Colpitts current-reused quadrature voltage-controlled oscillator (QVCO) based on capacitor coupling in TSMC 0.18um CMOS 1P6M process technology. Comparing to conventional parallel-coupled QVCO (P-QVCO), the proposed QVCO achieves a better phase noise and phase accuracy. The proposed QVCO operates from 4.57GHz to 5.02GHz. The measured phase noise at 1MHz offset frequency is -119 dBc/Hz and the measured phase error of quadrature signals arc 5 at 5CHz. With 1.8V power supply, the power consumption is 8.46mW. The figure of merit (FOM) of proposed QVCO is 183.7 dBc/Hz. The die area is 1x0.78mm(2)
A Low Phase Noise Quadrature VCO Using Symmetrical Tail Current-Shaping Technique
(2010-07-01)
Shen, I-Shing
;
Huang, Tze-Che
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Jou, Christina F.
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電信工程研究所
;
Institute of Communications Engineering
This letter presents a new symmetrical tail current-shaping technique to improve the phase noise of a quadrature voltage-controlled oscillator (QVCO). This proposed QVCO consists of two first-harmonic injection-locked oscillators (ILOs) and the outputs are injected back to the gates of the QVCO's tail transistors in order to shape the tail currents. A switching current path is provided between the two tail current sources in order to eliminate the asymmetric phenomenon of the tail currents. The measured phase noise can be improved by 4 dB using this technique. This CMOS LC-tank QVCO has been implemented using the TSMC 0.18 mu m mixed-signal/RF CMOS 1P6M technology and the die area is 0.7 x 1.1 mm(2). The total power consumption is 11.2 mW at the supply voltage of 1.4 V. The measured phase noise at 1 MHz offset is -119.3 dBc/Hz at the oscillation frequency of 5.28 GHz. The figure of merit (FOM) of the proposed QVCO is -183 dBc/Hz.
A Ultra Low Power 5.4-GHz Current-Reused VCO with Internal LC Series Resonance in 0.18-1-mu m CMOS Technology
(2010-01-01)
Shen, I-Shing
;
Ke, Han-Tzung
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Jou, Christina F.
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電信工程研究所
;
Institute of Communications Engineering
A novel circuit topology suitable for the implementation of CMOS voltage-controlled-oscillator (VCO) fabricated in TSMC 0.18-mu m has been presented in this paper. While current-reused structure can save dc power consumption dynamically, and measured dc power consumption at 1.2 V is about 0.9 mW. The measurement results exhibit a frequency tuning range of 140 MHz in the vicinity of 5.4 GHz. For high output level, we utilize the cascode structure to increase output swing and excite output power to -2.06 dBm at buffer. The measured phase noise at 1 MHz and DC current are -112.7 dBc/Hz and 0.75 mA, respectively. The result evaluated by means of a figure of merit is about -188 dBc/Hz.
A X-Band Capacitor-Coupled QVCO Using Sinusoidal Current Bias Technique
(2012-02-01)
Shen, I-Shing
;
Jou, Christina F.
;
電信工程研究所
;
Institute of Communications Engineering
This study introduces an X-band quadrature voltage-controlled oscillator (QVCO) based on two novel techniques: capacitor coupling and sinusoidal current biasing. The proposed QVCO achieves an excellent figure-of-merit (FOM) of 190.5 dBc/Hz. This study analyzes the properties of this QVCO, including its phase noise, oscillation frequency, and amplitude. To generate quadrature phase signals with low phase noise, the proposed design uses two capacitor-coupled LC-tank cores instead of active device-coupled cores. Sinusoidal currents through these capacitors bias the oscillator, increasing oscillation amplitude and reducing the phase noise contribution from cross-coupled transistors compared to existing QVCOs or VCOs biased with a constant current. These two techniques allow the proposed QVCO to achieve at least a theoretical 3 dB phase noise improvement compared to conventional LC-QVCOs. Implemented in a standard 0.18 mu m CMOS process, the proposed QVCO had a frequency tuning range of 9.2 similar to 10.4 GHz and a phase noise of -115.7 dBc/Hz@1 MHz from a carrier of 10.4 GHz while consuming 3.6 mW with 1.5 V voltage supply.
A-194 dBc/Hz FOM Interactive Current-Reused QVCO (ICR-QVCO) with Capacitor-Coupling Self-Switching Sinusoidal Current Biasing (CSSCB) Phase Noise Reduction Technique
(2015)
Wu, Kuan-I
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Shen, I-Shing
;
Jou, Christina F.
;
Chen, Charlie Chung-Ping
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電信工程研究所
This paper proposed a novel interactive current-reused QVCO (ICR-QVCO) architecture based on capacitor-coupling self-switching sinusoidal current biasing (CSSCB) phase noise reduction technique. These interactive generated quadrature outputs have minimum phase error arising from the mismatch due to process variation and construct the better quadrature phase relationship than ones with conventional QVCO structures. The measured phase noise at an offset of 1 MHz from 4.84 GHz is -125.84 dBc/Hz, which correspond to FOM of -194 dBc/Hz.