• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.98-104
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• 2009

In this paper, improved VCO(voltage controlled oscillator) with push-push structure and high impedance-inverter is designed and implemented. Two harmonic oscillators are combined into push-push structure. As a result, the fundamental suppression and the output power have been progressed. For the improved coupling characteristics between hair-pin resonator and two parallel microstrip line using high impedance inverter, the phase noise has been suppressed.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.387-390
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• 1998

In this paper, HBT's with lower phase noise and passive elements, such as resistors, capacitors and inductors, for resonance and impedance matching networks are designed, fabricated, tested, and carefully analysed, respectively, and then, they are integrated for the design and fabrication of functional X-band oscillators with lower phase noise. Epi-wafers for HBT's with the structure of graded $Al_{x}$G $a_{1-x}$ As emitter and C-doped base layer of 700.angs. thick were used to specially emphasize the improvement of $f_{T}$ and $f_{max}$, and the lowering of phase noise, in design aspects. At the test frequencies of 12GHz, capacitances of MIM capacitors, spiral inductor, and resistances are 0.5~10pF, 0.4~11.06nH, and 20~1,380.ohm., respectively. The emitter size of HBY's for the X-band MMIC oscillators is 3*10u $m^{2}$, and find chip size is 0.9*0.9m $m^{2}$..EX>.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.70-77
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• 1999

A miniaturized voltage controlled oscillator using multi-layer ceramic technology at PCS frequency band is designed and fabricated. To improve the phase noise characteristics and to reduce the size, the strip line which is embedded in a high performance multi-layer ceramic substrate is used as an inductor of VCO. And the fabricated VCO is very small size ($6mm\times6mm\times2mm$). At the bias condition of 3.3 V and 9mA, the output power and phase noise in the operating frequency range of 1,720~1,780 MHz are -3.7 dBm and -95 dBc/Hz at 10 KHz offset from the carrier, respectively. The phase noise and size are better than the conventional VCO using glass epoxy substrate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.959-968
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• 2000

In this paper, a low phase noise frequency synthesizer used to TX local oscillator in BWLL RF tranceiver is presented. The phase-locked stable 25GHz-band frequencies in BWLL TX LO are obtained by using 2 GHz baseband frequency synthesizer, sixth-harmonic frequency multiplier and frequency doubler at 12 GHz band frequency input. The 25 GHz band frequency synthesizer presented in this paper has 3-output frequencies at 24.92 GHz, 25.10 GHz, 25.26 GHz. At 24.92 GHz frequency the synthesizer has 0.44 dBm output power and shows -87.93 dBc/Hz(a 10 KHz), -109.54 dBc/Hz (a100 KHz) phase noise characteristics .

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.3 s.333
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• pp.25-32
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• 2005

In this papers, we first, therefore, designed VCO(voltage controlled oscillator) that is composed of the dielectric resonator and the varactor diode, and then designed and fabricated PLDRO(phase locked dielectric resonator oscillator) that is combined with the sampling phase detector and loop filter. The measured results of the fabricated PLDRO at 12.05 [GHz] show the output power is 13.54 [dBm], frequency tuning range approximately +/- 7.5 [MHz], and Power variation over the tuning range less than 0.2 [dB], respectively. The phase noise which effects on bits error rate in digital communication is obtained with -114.5 [dBc/Hz] at 100 [KHz] offset from carrier, and The second harmonic suppression is less than -41.49 [dBc]. These measured results are found to be more improved than those of VCO without adopting PLL, and the phase noise and power variation performance characteristics show the better performances than those of conventional PLL.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.811-818
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• 2016

A continuous fine-tuning phase locked loop with an additional negative feedback loop has been proposed. When the phase locked loop is out-of-lock, the phase locked loop has a fast locking characteristic using the continuous band-selection loop. When the phase locked loop is near in-lock, the bandwidth is narrowed with the fine loop. The additional negative feedback loop consists of a voltage controlled oscillator, a frequency voltage converter and its internal loop filter. It serves a negative feedback function to the main phase locked loop, and improves the phase noise characteristics and the stability of the proposed phase locked loop. The additional negative feedback loop makes the continuous fine-tuning loop work stably without any voltage fluctuation in the loop filter. Measurement results of the fabricated phase locked loop in $0.18{\mu}m$ CMOS process show that the phase noise is -109.6dBc/Hz at 2MHz offset from 742.8MHz carrier 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.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.12
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• pp.22-27
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• 2007

In this paper, a novel voltage-controlled oscillator (VCO) using the microstrip square open loop split ring resonator (OLSRR) is presented for reducing the phase noise. For this purpose, the square-shaped split ring resonator (SRR) haying the form of the microstrip square open loop is investigated. Compared with the microstrip square open loop resonator, the microstrip square OLSRR has the larger coupling coefficient value, which makes a higher Q value, and has reduced the phase noise of VCO. The VCO with 1.7V power supply has the phase noise of $-120\sim-116.5$ dBc/Hz @ 100 kHz in the tuning range, $5.746\sim5.854$ GHz. The figure of merit (FOM) of this VCO is $-200.33\sim-197$ dBc/Hz @ 100 kHz in the same tuning range.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.55-60
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• 2014

For an high speed communication, a 40GHz VCO was implemented using a 0.11um standard CMOS technology. The mm-wave VCO was designed by a LC type using a spiral inductor, and a simplified architecture with buffers and a smart biasing technique were used to get a high performance. The frequency range of the proposed VCO is 34~40GHz which is suitable for mm-Wave communication system. It has an output power of -16dBm and 16% tuning range. And the phase noise is -100.33dBc/Hz at 1MHz offset at 38GHz fundamental frequency. The total power consumption of VCO including PADs is 16.8mW with 1.2V supply voltage. The VCO achieves the FOMT of -183.8dBc/Hz which is better than previous VOCs.