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ABSTRACT: A 36 GHz LC-VCO with a digitally controllable transmission line (TL) inductor is presented in this work. The isolated metal strips used as artificial dielectrics are adopted underneath the inductor in the oscillator to enhance the effective permittivity and reduce substrate loss. Meanwhile, the potential of a portion of the metal strips are designed to be digitally controllable to vary the parasitic capacitance of the TL inductor. Thus, the entire frequency tuning range of the VCO adopting the TL inductor with digitally controllable artificial dielectrics can be extended. The increment of frequency tuning range introduced by the proposed technique depends on the amount and layer of the metal strips which are designed to be digitally controllable. The proposed VCO was fabricated using 0.13 μm CMOS RF technology. The measured operation frequency ranges from 36.01 to 36.71 GHz. The measured phase noise ranges from -93.66 to -101.7 dBc/Hz at 3 MHz offset. The entire circuit, including two output buffers, consumes 18 mW power under 1 V supply. The measured output spectrum of the VCO is higher than -13.3 dBm across the entire oscillation frequency band. The calculated FoM is 171.
Microwave and Millimeter Wave Technology (ICMMT), 2010 International Conference on; 06/2010
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ABSTRACT: This paper presents a two-stage wideband low noise amplifier (LNA) with active balun. The first stage adopts current bleeding and dc coupled common-drain feedback techniques to achieve high gain low noise figure and acceptable input matching over a wide frequency band. A conventional single-ended to differential convertor is used as a second stage. The proposed wideband LNA is designed for DVB-T application and implemented in 0.18-mum CMOS technology. The circuit achieves a 1 GHz bandwidth ranging from 10 MHz to 1 GHz over which the measured gain is 23 dB and the noise figure ranges from 1.61 to 3.81 dB. The measured gain ripple and phase differences in the entire pass band of the proposed LNA are less than 0.6 dB and 3.8deg, respectively. This LNA core dissipates 21.6 mW power.
Circuits and Systems, 2009. ISCAS 2009. IEEE International Symposium on; 06/2009
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ABSTRACT: A self-switched biasing quadrature voltage-controlled oscillator (VCO) is presented. It is implemented by directly injecting the oscillation signal of one VCO core into the other VCO core through the divided tail current sources without additional active devices for coupling. The proposed coupling structure automatically switches the NMOS field-effect transistors used in VCO cores and current sources from strong inversion to accumulation. Since the deep switching of MOSFETs was reported to physically reduce flicker noise, the proposed quadrature VCO (QVCO) is expected to improve the phase noise performance, which is confirmed experimentally. The designed QVCO using 0.18- mum CMOS technology operates from 1.86 to 2.2 GHz with a 17% frequency tuning range. The measured phase noise is from - 129.1 to - 134.5 dBc/Hz at a 1-MHz offset, which is really close to ideal simulation results with the NMOS model disabling the flicker noise components. The average measured phase noise is 7.2 dB below the simulated one with a flicker noise model, which verifies the physical reduction of flicker noise by deep switching of the MOSFET. The phase noise figure-of-merit ranges from 179 to 185 over the entire tuning range. The QVCO dissipates 20 mA from a 1.8-V supply.
IEEE Transactions on Microwave Theory and Techniques 03/2009; · 1.85 Impact Factor
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ABSTRACT: This work proposes an inductor-less programmable quadrature VCO which adopts a modified grounded active inductor with a PMOS resistor in the feedback path. The model of the active inductor using PMOS resistor feedback is also presented in this work, which is more accurate than the previous models by considering the effect of the parasitic capacitance in the feedback path. The programmable QVCO can oscillate in three different wireless bands. Therefore, it can be used in the multi-mode transceiver system or software-defined radio system.
Microwave Conference, 2007. APMC 2007. Asia-Pacific; 01/2008
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ABSTRACT: A novel linearization method is proposed for CMOS LNA design. The proposed LNA adopts two cascode FETs, one of which operates as a conventional current buffer delivering the fundamental current to the load and the other one works as a nonlinear current sinker absorbing the 3rd-order intermodulation distortion (IMD3) current generated by the common source FET. Both single-ended and differential structures are investigated at 2.14 GHz for WCDMA application. The simulation results shows that the single-ended LNA has an 18dBm IIP3 at 11.8 mW power consumption and the differential one has a 12dBm IIP3 at 24.3 mW power consumption
Circuits and Systems, 2006. ISCAS 2006. Proceedings. 2006 IEEE International Symposium on; 06/2006
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ABSTRACT: In this paper, we present a novel wide-band envelope detector comprising a fully-differential operational transconductance amplifier (OTA), a full-wave rectifier and a peak detector. To enhance the frequency performance of the envelop detector, we utilize a gyrator-C active inductor load in the OTA for wider bandwidth. Additionally, it is shown that the high-speed rectifier of the envelope detector requires high bias current instead of the sub-threshold bias condition. The experimental results show that the proposed envelope detector can work from 100-Hz to 1.6-GHz with an input dynamic range of 50-dB at 100-Hz and 40-dB at 1.6-GHz, respectively. The envelope detector was fabricated on the TSMC 0.18-um CMOS process with an active area of 0.65<sup>2</sup> mm<sup>2</sup>.
Radio Frequency Integrated Circuits Symposium, 2008. RFIC 2008. IEEE;
