• Title/Summary/Keyword: Varactor Diode

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Implementation of Tuneable Filter Using CPW Coupled Line and Varactor Diode

  • Park, Jeong-Heum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.9
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    • pp.40-44
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    • 2006
  • This study investigated a new tuneable bandpass filter based on coplanar waveguide coupled line structure, and using the varactor diode for tuning the center frequency of the filter. The filter was designed by a commercial simulator and had a tuning range of 180[MHz] from 0.95[GHz] to 1.13[GHz]. The filter acceptable values regarding the insertion loss was less than 3[dB] and its return loss greater than 12[dB]. The figure of merit of the implemented tuneable filter increased with the reverse bias voltage up to 14[V] on the varactor diode. The proposed filter has a promising future as it can be used in integration processes and in various materials as substrate.

A Novel Compact Tunable Bandpass Filter Loaded Varactor Diode on the DGS

  • Kim, Gi-Rae
    • Journal of information and communication convergence engineering
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    • v.8 no.3
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    • pp.263-266
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    • 2010
  • In this paper, a novel defected ground structure (DGS) pattern with enhanced effective capacitance (varactor diode) and a hole in PCB center is presented. The increase in effective capacitance enables the new DGS pattern to achieve a lower resonance than the DGS pattern for the same etched square dimension. The hole in the center also can make resonator frequency lower with better characteristic. According to the tunable characteristic of varactor diode, the resonant frequencies can be tunable. Simulation results show that a lower resonance is achieved with active device, compared to a common DGS pattern.

X-band Voltage Controlled Oscillator using Varactor Diode (바랙터 다이오드를 이용한 X-밴드 전압제어 발진기)

  • Park, Dong-Kook;Yun, Na-Ra;Choi, Yean-Ji;Kim, Yea-Ji
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.5
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    • pp.756-761
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    • 2009
  • In this paper, a X band voltage controlled oscillator is proposed. The oscillator uses a transistor as an oscillating element and its oscillating frequencies are controlled by the tuning voltage of varactor diode. Using the circuit simulation tools, the matching circuits between the transistor and varactor diode, its input and output matching circuits, and a feedback circuits are designed. The measured results of the fabricated oscillator show that its oscillation frequencies are from 10.50GHz to 10.88GHz according to the turning voltages of 1V to 18V, its output power levels are about 4.3dBm, and its phase noise is around -43.5dBc/Hz at 100kHz offset frequency of 10.5GHz.

Study of Design and Fabrication of GaAs Varactor diode (GaAs 버렉터 다이오드의 설계와 제작에 관한 연구)

  • Choi, Seok-Gyu;Baek, Young-Hyun;Beak, Tea-Jong;Kim, Mi-Ra;Rhee, Jin-Koo
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.387-388
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    • 2008
  • In this paper, we have designed and fabricated hyperabrupt varactor diodes. Capacitance variations of hyperabrupt-doped varactor diodes are larger than those of uniform-doped varactor diodes. The measured reverse breakdown voltage of the fabricated varactor diodes was about 20 V. For the anode contact diameter of $50\;{\mu}m$, the maximum capacitance of the fabricated varactor diode was 2.1 pF and the minimum capacitance 0.44 pF. Therefore, the $C_{max}/C_{min}$ ratio was 4.77. Also, for the anode contact diameter of $60\;{\mu}m$, the maximum and minimum capacitances were 2.9 and 0.62 pF, respectively. And, thus, the $C_{max}/C_{min}$ ratio was 4.64.

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A Design of Dual Band LNA for RFID Using Varactor Diode (Varactor를 이용한 RFID 이증 대역 LNA 설계)

  • Choi, Jin-Kyu;Ko, Jae-Hyeong;Chang, Se-Wook;Kim, Hyeong-Seok
    • Proceedings of the KIEE Conference
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    • 2008.05a
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    • pp.151-152
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    • 2008
  • In this paper, a dual band LNA (Low Noise Amplifier) with a matching circuit using varactor diode is designed for 912MHz and 2450MHz RFID system. The operating frequency is controlled by the bias voltage applied to the varactor diode. The measured results demonstrate that gain is 13.6dB and 6.8dB at 912MHz and 2450MHz. The measured NF (Noise Figure) is 1.4dB and 3.1dB at 912MHz and 2450MHz, respectively.

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A Study on the Diplexer Switch of High Isolation Using Varactor Diode (바랙터 다이오드를 이용한 높은 격리도를 갖는 DIPLEXER 스위치에 관한 연구)

  • Kang Myung-Soo;Park Jun-Seok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.4
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    • pp.178-184
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    • 2005
  • In this paper, using diplexer structure and varactor diode controlled by reverse bias voltage for diplexer switch gives possibilities to improve isolation and current characteristics. 1 have newly designed switch with high isolation by application varactor diode corresponding to capacitor of diplexer. The low-pass filter for proposed tunable diplexer passes the microwave signal in the bandwidth for wireless cellular network systems and high-pass filter passes it in the bandwidth for wireless personal communication services (PCS) network systems. As the capacitance of the low-pass filter increases, the cut-off frequency can be moved to low frequency, so that the switch is on state in cellular bandwidth and off state in the PCS bandwidth, in contrast to, as the capacitance for attenuation characteristic of high-pass filter increases, it can be moved to high frequency, so that the switch is off state and on state in the cellular bandwidth. it is possible to improve isolation and current consumption characteristics by application diplexer design methods and varactor diode. 1 expect that the tunable diplexer circuit and design methods should be able to find applications on MMIC and low temperature copired ceramic (LTCC).

High Performance W-band VCO for FMCW Applications (FMCW 응용을 위한 우수한 성능의 W-band 도파관 전압조정발진기)

  • Ryu, Keun-Kwan;Rhee, Jin-Koo;Kim, Sung-Cha
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.4A
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    • pp.214-218
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    • 2012
  • In this paper, we reported on a high performance waveguide VCO(voltage controlled oscillator) for FMCW applications. The waveguide VCO consists of a GaAs Gunn diode, a varactor diode, and two bias posts with low pass filter(LPF). The cavity is designed for fundamental mode at 47 GHz and operated at second harmonic of 94 GHz center frequency. The developed waveguide VCO has 1.095 GHz bandwidth, 590 MHz linearity with 1.69% and output power from 14.86 to 15.93 dBm. The phase noise is under -95 dBc/Hz at 1 MHz offset.

Development of the High Performance 94 GHz Waveguide VCO (우수한 성능의 94 GHz 도파관 전압조정발진기의 개발)

  • Ryu, Keun-Kwan;Kim, Sung-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.5
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    • pp.1035-1039
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    • 2012
  • In this paper, we developed a 94 GHz waveguide VCO(voltage controlled oscillator) using a GaAs-based Gunn diode and a varactor diode. The cavity is designed for fundamental mode at 47 GHz and operated at second harmonic of 94 GHz. Bias posts for diodes operate as LPF(low pass filter) and resonator. The fabricated waveguide VCO achieves an oscillation bandwidth of 760 MHz. Output power is from 12.61 to 15.26 dBm and phase noise is -101.13 dBc/Hz at 1 MHz offset frequency from the carrier.

A Compact Tunable Bandpass Filter Using Coupled Metamaterial Resonators with Varactor Diode

  • Kim, Gi-Rae
    • Journal of information and communication convergence engineering
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    • v.8 no.5
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    • pp.484-488
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    • 2010
  • In this paper, we present a novel tunable microstrip bandpass filter based on split ring resonators (SRRs). The varactors are reverse-biased semiconductor diode, and are connected between the concentric rings of the SRR. An individual varactor loaded SRR based bandpass tunable filter module is analyzed. Then a second order tunable filter with 7% fractional bandwidth and a tuning range from 2.75 to 2.86 GHz is assembled from basic filter modules. The simulator HFSS (V10) is used to design the tunable filter and to simulate. The results show good characteristics is created.

Expansion of Variable Range of Oscillation Frequency of Active Phased Array Antenna by a Varactor Diode (바랙터다이오드에 의한 능동 위상차 배열 안테나의 발진 주파수 가변 범위의 확장)

  • 최영규
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.11
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    • pp.521-528
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    • 2003
  • A varactor diode was utilized in order to expand variable range of the natural oscillation frequency of an active phased-array antenna. We have conformed experimentally that the variable range of the natural oscillation frequency was expanded about three times in the oscillator controlled by the varactor diode. When frequency difference was given to the oscillators in the two elements antenna system, phase difference was appeared between the oscillators. The 2-, 3-, 5-elements patch antenna array was composed for the beam scanning experiments. All the above patch antennas showed good phased array characteristics. The experimental results are as follows that the scanning angle of the 2-elements array antenna is 28.6$^{\circ}$, the 3-elements array antenna is 29.4$^{\circ}$, and the 5-elements array antenna is 26.2$^{\circ}$.