• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.890-893
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• 2003

In this paper, we have designed the fractional-N frequency synthesizer for bluetooth system using 0.35-um CMOS technology and 3.3-V single power supply. The designed synthesizer consist of phase-frequency detector (PFD), charge pump, loop filter, voltage controlled oscillator (VCO), frequency divider, and sigma-delta modulator. A dead zone free PFD is used and a modified charge pump having active cascode transistors is used. A Multi-modulus prescaler having CML D flip-flop is used and VCO having a tuning range from 746 MHz to 2.632 GHz at 3.3 V power supply is used. Total power dissipation is 32 mW and phase noise is -118 dBc/Hz at 1 MHz offset.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.784-794
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• 1996

In this papre, the design and the fabrication of the surface mountable voltage controlled oscillator is described for local oscillator in PCS(WACS/TDMA) handset. The VCO employs two silicon bipolar transistors of $f_{gamma}$ of 4 GHz as active devices. These are asembled to form the VCO on the 4 layer PCB of the size $12{\times}10mm$which provides the strip line resonator at the third layer. The fabricated VCO shows tuning rage over 50 MHz, phase noise -100 dBc/Hz at the 100 kHz frequency offset, and 0 dBm output power with the consumption of 22 mA at 3V. It is belived that the size will be more reduced by employing 1005 chip components and that the current consumption will be improved by employing transistors of higher $f_{gamma}$.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.194-199
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• 1997

When voltage or current gets out of the magnetic sensor as it is, we have often faced the problems such as introduction of noise and loss of voltage. In order to reduce these problems, a 2 drain MAGFET operating in the saturation region and fabricated by CMOS process, the system of I/V converter, VCO with operational amplifier, and V/F conversion circuits with Schmitt Trigger are designed and fabricated in one package. The absolute sensitivity of magnetic sensor shows 1.9 V/T and the product sensitivity is $3.2{\times}10^{4}\;V/A{\cdot}T$. The characteristic of V/F conversion is very stabilized and has the value of 190 kHz/T.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.961-966
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• 2009

In this paper, a novel voltage-controlled oscillator(VCO) using the metamaterial broadside coupled spiral resonators(BC-DSRs) is presented for reducing the phase noise. For reducing of the phase noise, the series spiral structures have been applied for the signal plane and ground plane at each in order to have the large coupling. Compared with the conventional VCO, the proposed VCO has the larger coupling coefficient constant, which makes a higher Q-factor and has reduced the phase noise of the VCO. The proposed VCO has the phase noise of $-121{\sim}-117.16\;dBc$/Hz at 100 kHz in the tuning range, $5.749{\sim}5.853\;GHz$. The figure of merit(FOM) of this VCO is $-198.45{\sim}-194.77\;dBc$/Hz at 100 Hz in the same tuning range, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.183-192
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• 2000

In this paper, the dual looped CMOS PLL with 3-250MHz input locking range at a single 13.3V is designed. This paper proposed a new PLL architecture with a current pumping algorithm to improve voltage-to-frequencylinearity of VCO(Voltage Controlled Oscillator). The designed VCO operates at a wide frequency range of75.8MHz-lGHz with a high linearity. Also, PFD(Phase frequency Detector) circuit preventing voltage fluctuation of the charge pump with loop filter circuit under the locked condition is designed. The simulation results of the PLL using 0.6 um N-well single poly triple metal CMOS technology illustrate a locking time of 3.5 us, a power dissipation of 92mW at 1GHz operating frequency with 125MHz of input frequency. Measured results show that the phase noise of VCO with V-I converter is -100.3dBc/Hz at a 100kHz offset frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.627-634
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• 2010

In this paper, a novel voltage-controlled oscillator(VCO) using the complimentary bifilar archimedean spiral resonator(CBASR) is presented for reducing the phase noise characteristic. A CBASR has compact dimension, a sharp skirt characteristic in stopband, a low insertion loss in passband, and a large coupling coefficient value, which makes a high Q value and improve the phase noise of VCO. The proposed VCO has the oscillation frequency of 2.396~2.502 GHz in the tuning voltage of 0~5 V, the output power of 7.5 dBm and phase noise of -119.16~-120.2 dBc/㎐ at the offset frequency of 100 kHz in tuning range.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.223-228
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• 2018

In this paper the water sensor using a coaxial cavity resonator is designed and manufactured. The water sensor which can sense water drop linearly has been constructed with voltage controlled oscillator(VCO), coaxial cavity resonator, RF switch, RF detector, A/D converter, DAC and micro controller. The operating frequency range of the designed water sensor is from 2.5GHz to 3.2GHz and the input voltage and current source are 24[V/DC] and 1[A]. The designed sensor circuit includes VCO, RF switch, RF detector which varies the frequency characteristics of the devices in the high frequency of 3GHz. And so we should correct the error of the frequency characteristics of those devices in the sensor circuit. To do this, we make the reference path which switches the signals to the RF detector directly without sending it to the resonator. According to the result of simulation and measurement, we can see that there is 0-50MHz difference between simulated resonator frequency and manufactured resonator frequency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.11
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• pp.56-60
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• 2009

In this paper, a novel voltage controlled oscillator (VCO) has been presented by using the microstrip square multiple spiral resonator for reducing the phase noise of VCO. The microstrip multiple square resonator has the large coupling coefficient value, which makes a high Q value, and has reduced phase noise of VCO. The VCO with 1.8 V power supply has phase noise of -115.0~-117.34 dBc/Hz @100 kHz in the tuning range, 8.935~9.4 GHz. When it has been compared with microstrip square multiple spiral resonator and coventional spiral resonator, the reduced Q value has been -32.7 dB and -57.6 dB respectively. This low phase noise VCO could ve available to a VCO in X-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.964-969
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• 2007

A regulated low phase noise differential colpitts VCO(Voltage Controlled Oscillator) for mobile RFID system is presented. The differential colpitts VCO meets the dense reader environment specifications. The VCO use a $0.35{\mu}m$ technology and achieves tuning range $1.55{sim}2.053 GHz$. Measuring 910 MHz frequency divider output, phase noise performance is -106 dBcMz and -135dBc/Hz at 40 kHz and 1MHz offset, respectively. 5-bit digital coarse-tuning and accumulation type MOS varactors allow for 28.2% tuning range, which is required to cover the LO frequency range of a UHF Mobile RFID system, Optimum design techniques ensure low VCO gain(<45 MHz/V) for good interoperability with the frequency synthesizer. To the author' knowledge, this differential colpitts VCO achieves a figure of merit(FOM) of 1.93dB at 2-GHz band.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.35-38
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• 2010

A fully integrated parallel-coupled 6-GHz quadrature voltage-controlled oscillator (QVCO) has been designed. The symmetrical parallel-coupled quadrature VCO is implemented using 0.13-${\mu}m$ CMOS process. The measured phase noise is -101.05 dBc/Hz at an offset frequency of 1 MHz. The tuning range of 710 MHz is achieved with a control voltage ranging from 0.3 to 1.4 V. The average output phase error is about $1.26^{\circ}$ including cables and connectors. The QVCO dissipates 10 mA including buffer from the 1.5 V supply voltage. The output characteristic of the differential injection-locked frequency divider (DILFD), which has similar topology to the QVCO, is presented.