• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.293-297
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• 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.

• 대한전자공학회논문지SD
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• 제47권8호
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• pp.64-72
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• 2010

본 논문은 UWB주파수 합성기용 광대역 전압 제어 발진기로 시그마-델타 모듈레이션을 이용하여 미세한 성긴 튜닝을 구현하였다. 제안된 성긴 튜닝 방법은 위상 잡음 성능의 저하 없이 작은 유효 주파수 해상도를 제공한다. 3단계의 성긴 튜닝구조로 전압제어 발진기는 광대역과 미세 튜닝 단계를 동시에 구현한다. 본 전압 제어기를 포함한 주파수 합성기는 0.13 ${\mu}m$ CMOS공정으로 구현되었고, 5.8-6.8 GHz의 대역에 3.9 kHz의 유효 주파수 해상도를 갖는다. 측정된 위상 잡음은 1 MHz 오프셋에서 -108 dBc/Hz이고, 5.9 mW 전력 소모로 16.8 %의 튜닝 범위를 갖으며, 튜닝 범위를 갖는 Figure-of-merit(FoM)은 -181.58 dBc/Hz이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.218-220
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• 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.

• 한국전자파학회논문지
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• 제20권6호
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• pp.570-579
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• 2009

본 논문에서는 개루프 설계 방법을 이용하여, 전기적주파수조정범위가 확장된 전압제어유전체공진기발진기(Vt-ORO: Voltage-tuned Dielectric Resonator Oscillator)를 설계하였다. 설계된 전압제어유전체공진기발진기는 공진부, 증폭부, 위상천이부로 구성하였다. 발진조건을 만족하기 위하여, 각 부에서의 크기와 위상을 결정하였다. 각 부를 연결하여 측정한 S-피라미터는 개루프 발진조건을 만족하였다. 또한, 측정된 개루프의 군지연(group delay)로부터 전기적주파수조정범위(electrical frequency tuning-range)를 수식으로 도출하였다. 이와 같이 설계된 개루프의 입출력을 연결하고 폐루프로 구성하여 전압제어유전체공진기발진기를 구현하였다. 그 결과, 0$\sim}$10 V의 조정전압으로 중심주파수 5.3 GHz에서 전기적주파수조정범위는 수식으로 도출한 값과 근사한 82 MHz를 얻었고, 이는 선형적인 변화를 보였다. 이 때, 위상잡음은 100 kHz offset에서 -104${\pm}$1 dBc/Hz, 출력전력은 5.86${\pm}$1 dBm로 평탄함을 보였다.

• ETRI Journal
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• 제33권2호
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• pp.201-209
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• 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
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• 제5권4호
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• pp.466-476
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• 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.

• 전자공학회논문지A
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• 제33A권2호
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• pp.78-86
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• 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.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.21-24
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• 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.

• 한국공작기계학회논문집
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• 제14권5호
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• pp.35-40
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• 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.

• 한국통신학회논문지
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• 제38A권12호
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• pp.991-997
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• 2013

본 논문에서는 아날로그필터를 위한 새로운 구조의 주파수 제어 방식(frequency tuning scheme)과 트랜스컨덕턴스(gm) 가변 범위가 넓은 트랜스컨덕터(OTA: Operational transconductor amplifier) 회로를 제안하였다. 제안된 주파수 제어 방식은 트랜스컨덕터와 커패시터로 구성된 1차 저역통과필터의 시정수와 커패시터에 일정 전압이 충전되는데 걸리는 시간과의 관계식을 이용한 것으로 전압제어필터 방식과 유사하게 간단한 구조를 가지며, 기준신호로 순수 정현파를 필요로 하지 않고, 시스템 클럭 또는 외부 수정 발진 회로를 통해 쉽게 얻을 수 있는 클럭 펄스를 사용할 수 있다는 장점이 있다. 또한, 클럭 주파수가 고정된 조건에서도 복잡한 구조의 커패시터 어레이를 사용하지 않고 다중 대역 지원을 목적으로 차단 주파수를 가변하면서 제어할 수 있다. 그리고 모의 실험을 통해 제안된 자동 주파수 제어회로의 동작을 확인하였다.