• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.293-297
• /
• 2009

In this thesis, design of a VCO(Voltage controlled Oscillator) with a novel tuning mechanism is presented for the Radar system. This circuit, the 9.5 GHz oscillator is designed and implemented by restructuring microstrip resonator to raise Q value and to require a wide frequency tuning range. This product is fabricated on 2.6 Teflon substrate and device is NE722S01. In this paper, The new microstrip resonator VCO is proposed to achieve the characteristic of a wide frequency tuning range. This microstrip resonator VCO shows the phase noise characteristic of -108.3 dBc/Hz at 1 MHz offset from the fundamental frequency, the output power of 5.7 dBm and the second harmonic suppression of -38 dBc for the VCO are obtained. The manufacture VCO shows a frequency tuning range of 193.8 MHz. The proposed micro trip resonator VCO can be used for X-band Radar System with required tuning range.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.8
• /
• pp.64-72
• /
• 2010

This paper presents a wide range VCO with fine coarse tuning step using a sigma-delta modulation technique for UWB frequency synthesizer. The proposed coarse tuning scheme provides the low effective frequency resolution without any degradation of phase noise performance. With three steps coarse tuning, the VCO has wide tuning range and fine tuning step simultaneously. The frequency synthesizer with VCO was implemented with 0.13 ${\mu}m$ CMOS technology. The tuning range of the VCO is 5.8 GHz~6.8 GHz with the effective frequency resolution of 3.9 kHz. It achieves the measured phase noise of -108 dBc/Hz at 1 MHz offset and a tuning range 16.8 % with 5.9 mW power. The figure-of-merit with the tuning range is -181.5 dBc/Hz.

• Proceedings of the IEEK Conference
• /
• summer
• /
• pp.218-220
• /
• 2004

A new wide-band VCO topology using Miller capacitance is proposed. Contrary to conventional VCO using the Miller capacitance where the variable amplifier gain is negative, the proposed VCO uses both the negative and positive variable amplifier gain to enhance the frequency tuning range significantly. The proposed VCO is simulated using HSPICE. The simulations show that 410MHz and 220MHz frequency tuning range are obtained using the negative .and positive variable amplifier gain, respectively. The tuning range of the proposed VCO is $23\%$ of the center frequency(2.8GHz). The phase noise is -104dBc/Hz at 1MHz offset by simple model. The operating current is only 3.84mA at 2.5V power supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.6
• /
• pp.570-579
• /
• 2009

In this paper, we presented a Vt-DRO with a wide electrical frequency tuning range, using open-loop gain method. The Vt-DRO was composed of 3-stages, resonator, amplifier and phase shifter. In order to satisfy an oscillation condition, we determined magnitude and phase of each stage. The measured S-parameter of cascaded 3-stages shows open-loop oscillation condition. Also, using measured open loop group delay, we derived the relation for electrical frequency tuning range. The Vt-DRO was implemented by connecting the input and the output of the designed open-loop and resulted in closed-loop. As a results, tuning-range of Vt-DRO is 82 MHz, which is close to the predicted results for tuning voltage 0${\sim}$10 V and shows linear frequency tuning at the center frequency of 5.3 GHz. The phase noise is -104 ${\pm}$1 dBc/Hz at 100 kHz offset frequency and power is 5.86${\pm}$1 dBm respectively.

• ETRI Journal
• /
• v.33 no.2
• /
• pp.201-209
• /
• 2011

This paper presents a wide-band fine-resolution digitally controlled oscillator (DCO) with an active inductor using an automatic three-step coarse and gain tuning loop. To control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. To cover the wide tuning range, a three-step coarse tuning scheme is used. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. The DCO tuning range is 58% at 2.4 GHz, and the power consumption is 6.6 mW from a 1.2 V supply voltage. An effective frequency resolution is 0.14 kHz. The phase noise of the DCO output at 2.4 GHz is -120.67 dBc/Hz at 1 MHz offset.

• Current Optics and Photonics
• /
• v.5 no.4
• /
• pp.466-476
• /
• 2021

Frequency-multiplication technology based on microwave photonic principles can be used to generate microwave and millimeter wave signals with a wide frequency tuning range. However, the existing cascaded external modulation frequency-tupling scheme needs to ensure the phase coherence of the modulated Radio Frequency (RF) signal, while the phase modulation directly limits the frequency tuning range of the external modulation frequency multiplication. In this paper, a novel approach for generating an incoherent frequency 12-tupling signal with cascade modulation is proposed. The structure of cascaded dual-parallel Mach-Zehnder modulators can generate a frequency 12-tupling signal. The proposed structure uses no filter or phase control of the RF driving signal. Microwave photonic frequency-tupling was realized under incoherent conditions. Software simulations and experiments validated the proposed structure and proved that it can generate frequency 12-tupling microwave signals under incoherent conditions. Both the frequency range and reliability of the frequency-tupling system has been improved by the proposed structure.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.2
• /
• pp.78-86
• /
• 1996

Solid-state devices can be directly integrated with a planar antenna to form active antenna elements. In this paper, the voltage controlled oscillator (VCO) is designed and fabricated at 2.4 to 2.5 GHz using a microstrip patch antenna. A varactor diode is used as avariable reactance. The predicted frequency tuning range of the VCO is 2.448 to 2.498 GHz in the design procedure and the fabricated VCO has 2.446 to 2.498 GHz frequency tuning range when the varactor tuning voltage is varied from 0 to 11V. Transmitted power output of the patch antenna which serves both as a rsonator and a radiating element for VCO is about 18 mW over this tuning range.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.21-24
• /
• 2002

This paper presents a fully integrated, wide tuning range differential CMOS voltage-controlled oscillator, tuned by pMOS-varactors. VCO utilizing a novel tuning scheme is reported. Both coarse digital tuning and fine analog tuning are achieved using pMOS-varactors. The VCO were implemented in a 0.18-fm standard CMOS process. The VCO tuned from 1.8㎓ to 2.55㎓ through 2-bit digital and analog input. At 1.8V power supply voltage and a total power dissipation of 8mW, the VCO features a phase noise of -126㏈c/㎐ at 3㎒ frequency offset.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.5
• /
• pp.35-40
• /
• 2005

An experimental Investigation of the basic characteristics of a micro-cantilever sensor was performed by inspecting the amplitude and frequency characteristics of a commercial tuning fork (TF). Application of acetone and ethanol with a volume of $1{\mu}l$ on the tine of a vibrating tuning fork causes immediate response in its amplitude and frequency characteristics. It has been shown that the tuning fork has ability to recognize a chemical agent with high sensitivity. The theoretical sensitivity of mass loading is in the range of $\~0.1Hz/ng$. Quartz tuning forks are routinely made using standard microfabrication process, thus suggesting the possibility of microfabrication of micro quart sensors.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.12
• /
• pp.991-997
• /
• 2013

A new frequency tuning scheme and a transconductor with a wide tuning range and low harmonic distortion is presented. This frequency tuning technique is based on the relationship between the time-constant and the elapsed times in charging a capacitor up to a certain level. Its structure is as simple as that of a conventional tuning scheme using a VCF(Voltage-Controlled Filter) and it does not need a pure sine wave but uses a CLK(Clock) pulse as a reference signal, which is easily obtained from on-chip system clocks or external X-tal oscillators. When a certain reference CLK is given, without complex capacitor arrays the pole frequency of the filter can be controlled continuously in the frequency domain. Simulation results are presented to confirm the operation of the proposed approach.