The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

Junxiang Ge - One of the best experts on this subject based on the ideXlab platform.

  • The Design Method of the Active Negative Group Delay Circuits Based on a Microwave Amplifier and an RL-Series Network
    IEEE Access, 2018
    Co-Authors: Ningdong Li, Blaise Ravelo, Qizheng Ji, Binhong Li, Junxiang Ge
    Abstract:

    This paper addresses a circuit theory regarding the negative group Delay (NGD) principle. The methodology for characterizing this unfamiliar NGD function is described. The basic NGD topology under study is typically an active cell composed of an RF low-noise amplifier (LNA) and an RL-series passive network. It acts as a low-pass NGD topology. The family of the bandpass NGD cell is identified from the low-pass to the bandpass transform. The NGD circuit theory under study is essentially built with the S-parameter approach. The main characteristics of the proposed NGD topology and properties of the NGD level, cut-off frequencies or bandwidth, central frequency, and figure-of-merit are established. The NGD cell is synthesized using the LNA S-parameter model. A method for designing the lowand bandpass NGD cells as a function of the specified NGD values is presented. The NGD cell parameter calculations as functions of the expected NGD level, insertion loss, and reflection coefficient are introduced. Proof-of-concept NGDs are synthesized, designed, simulated, and fabricated to understand and validate the proposed NGD low-pass and bandpass functions. As expected, low-pass and bandpass NGD aspects are obtained. The low-pass NGD Circuits present an NGD level of approximately -5 ns over the bandwidth fc = 25 MHz. Next, bandpass NGD Circuits were synthesized to operate at approximately 0.5 GHz over the bandwidth Δf = 50 MHz with an NGD level of approximately -10 ns. The measured results of the low-pass and bandpass NGD are in good agreement with the theoretical prediction obtained with simple lumped Circuits. Different applications of the unfamiliar NGD function are described.

  • the design method of the active negative group Delay Circuits based on a microwave amplifier and an rl series network
    IEEE Access, 2018
    Co-Authors: Ningdong Li, Blaise Ravelo, Qizheng Ji, Binhong Li, Junxiang Ge
    Abstract:

    This paper addresses a circuit theory regarding the negative group Delay (NGD) principle. The methodology for characterizing this unfamiliar NGD function is described. The basic NGD topology under study is typically an active cell composed of an RF low-noise amplifier (LNA) and an RL-series passive network. It acts as a low-pass NGD topology. The family of the bandpass NGD cell is identified from the low-pass to the bandpass transform. The NGD circuit theory under study is essentially built with the S-parameter approach. The main characteristics of the proposed NGD topology and properties of the NGD level, cut-off frequencies or bandwidth, central frequency, and figure-of-merit are established. The NGD cell is synthesized using the LNA S-parameter model. A method for designing the low- and bandpass NGD cells as a function of the specified NGD values is presented. The NGD cell parameter calculations as functions of the expected NGD level, insertion loss, and reflection coefficient are introduced. Proof-of-concept NGDs are synthesized, designed, simulated, and fabricated to understand and validate the proposed NGD low-pass and bandpass functions. As expected, low-pass and bandpass NGD aspects are obtained. The low-pass NGD Circuits present an NGD level of approximately −5 ns over the bandwidth fc = 25 MHz. Next, bandpass NGD Circuits were synthesized to operate at approximately 0.5 GHz over the bandwidth $\Delta \text{f}\,\,=50$ MHz with an NGD level of approximately −10 ns. The measured results of the low-pass and bandpass NGD are in good agreement with the theoretical prediction obtained with simple lumped Circuits. Different applications of the unfamiliar NGD function are described.

Kazuhiko Honjo - One of the best experts on this subject based on the ideXlab platform.

  • group Delay equalized uwb ingap gaas hbt mmic amplifier using negative group Delay Circuits
    IEEE Transactions on Microwave Theory and Techniques, 2009
    Co-Authors: Ryo Ishikawa, Kazuhiko Honjo
    Abstract:

    A negative group Delay (NGD) circuit has been employed to equalize a group Delay variation in a broadband ultra-wideband (UWB) InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) amplifier. Using the NGD circuit, a part of a salient group Delay characteristic in the operation band of broadband amplifiers can be suppressed without an increase of the entire group Delay. The MMIC amplifier has a steep group Delay increase in the lower frequency region of the full-band UWB band (3.1-10.6 GHz) due to the sum of phase variations near the cutoff frequencies of the HBTs. The NGD circuit has been inserted to reduce this increase of the group Delay in the UWB band. By adding a three-cell NGD circuit while considering input and output matching at the input side of the MMIC amplifier, the group Delay variation is decreased by 78%. However, gain was also decreased by insertion of the multistage NGD circuit. In an attempt to avoid this decrease in gain, a one-cell NGD circuit was inserted into the feedback loop of the MMIC amplifier, and as a result, we were able to decrease the group Delay variation by 79%, with minimal gain deterioration.

  • Group Delay Equalized UWB InGaP/GaAs HBT MMIC Amplifier Using Negative Group Delay Circuits
    IEEE Transactions on Microwave Theory and Techniques, 2009
    Co-Authors: Ryo Ishikawa, Kazuhiko Honjo
    Abstract:

    A negative group Delay (NGD) circuit has been employed to equalize a group Delay variation in a broadband ultra-wideband (UWB) InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) amplifier. Using the NGD circuit, a part of a salient group Delay characteristic in the operation band of broadband amplifiers can be suppressed without an increase of the entire group Delay. The MMIC amplifier has a steep group Delay increase in the lower frequency region of the full-band UWB band (3.1-10.6 GHz) due to the sum of phase variations near the cutoff frequencies of the HBTs. The NGD circuit has been inserted to reduce this increase of the group Delay in the UWB band. By adding a three-cell NGD circuit while considering input and output matching at the input side of the MMIC amplifier, the group Delay variation is decreased by 78%. However, gain was also decreased by insertion of the multistage NGD circuit. In an attempt to avoid this decrease in gain, a one-cell NGD circuit was inserted into the feedback loop of the MMIC amplifier, and as a result, we were able to decrease the group Delay variation by 79%, with minimal gain deterioration.

Ningdong Li - One of the best experts on this subject based on the ideXlab platform.

  • The Design Method of the Active Negative Group Delay Circuits Based on a Microwave Amplifier and an RL-Series Network
    IEEE Access, 2018
    Co-Authors: Ningdong Li, Blaise Ravelo, Qizheng Ji, Binhong Li, Junxiang Ge
    Abstract:

    This paper addresses a circuit theory regarding the negative group Delay (NGD) principle. The methodology for characterizing this unfamiliar NGD function is described. The basic NGD topology under study is typically an active cell composed of an RF low-noise amplifier (LNA) and an RL-series passive network. It acts as a low-pass NGD topology. The family of the bandpass NGD cell is identified from the low-pass to the bandpass transform. The NGD circuit theory under study is essentially built with the S-parameter approach. The main characteristics of the proposed NGD topology and properties of the NGD level, cut-off frequencies or bandwidth, central frequency, and figure-of-merit are established. The NGD cell is synthesized using the LNA S-parameter model. A method for designing the lowand bandpass NGD cells as a function of the specified NGD values is presented. The NGD cell parameter calculations as functions of the expected NGD level, insertion loss, and reflection coefficient are introduced. Proof-of-concept NGDs are synthesized, designed, simulated, and fabricated to understand and validate the proposed NGD low-pass and bandpass functions. As expected, low-pass and bandpass NGD aspects are obtained. The low-pass NGD Circuits present an NGD level of approximately -5 ns over the bandwidth fc = 25 MHz. Next, bandpass NGD Circuits were synthesized to operate at approximately 0.5 GHz over the bandwidth Δf = 50 MHz with an NGD level of approximately -10 ns. The measured results of the low-pass and bandpass NGD are in good agreement with the theoretical prediction obtained with simple lumped Circuits. Different applications of the unfamiliar NGD function are described.

  • the design method of the active negative group Delay Circuits based on a microwave amplifier and an rl series network
    IEEE Access, 2018
    Co-Authors: Ningdong Li, Blaise Ravelo, Qizheng Ji, Binhong Li, Junxiang Ge
    Abstract:

    This paper addresses a circuit theory regarding the negative group Delay (NGD) principle. The methodology for characterizing this unfamiliar NGD function is described. The basic NGD topology under study is typically an active cell composed of an RF low-noise amplifier (LNA) and an RL-series passive network. It acts as a low-pass NGD topology. The family of the bandpass NGD cell is identified from the low-pass to the bandpass transform. The NGD circuit theory under study is essentially built with the S-parameter approach. The main characteristics of the proposed NGD topology and properties of the NGD level, cut-off frequencies or bandwidth, central frequency, and figure-of-merit are established. The NGD cell is synthesized using the LNA S-parameter model. A method for designing the low- and bandpass NGD cells as a function of the specified NGD values is presented. The NGD cell parameter calculations as functions of the expected NGD level, insertion loss, and reflection coefficient are introduced. Proof-of-concept NGDs are synthesized, designed, simulated, and fabricated to understand and validate the proposed NGD low-pass and bandpass functions. As expected, low-pass and bandpass NGD aspects are obtained. The low-pass NGD Circuits present an NGD level of approximately −5 ns over the bandwidth fc = 25 MHz. Next, bandpass NGD Circuits were synthesized to operate at approximately 0.5 GHz over the bandwidth $\Delta \text{f}\,\,=50$ MHz with an NGD level of approximately −10 ns. The measured results of the low-pass and bandpass NGD are in good agreement with the theoretical prediction obtained with simple lumped Circuits. Different applications of the unfamiliar NGD function are described.

Ryo Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • group Delay equalized uwb ingap gaas hbt mmic amplifier using negative group Delay Circuits
    IEEE Transactions on Microwave Theory and Techniques, 2009
    Co-Authors: Ryo Ishikawa, Kazuhiko Honjo
    Abstract:

    A negative group Delay (NGD) circuit has been employed to equalize a group Delay variation in a broadband ultra-wideband (UWB) InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) amplifier. Using the NGD circuit, a part of a salient group Delay characteristic in the operation band of broadband amplifiers can be suppressed without an increase of the entire group Delay. The MMIC amplifier has a steep group Delay increase in the lower frequency region of the full-band UWB band (3.1-10.6 GHz) due to the sum of phase variations near the cutoff frequencies of the HBTs. The NGD circuit has been inserted to reduce this increase of the group Delay in the UWB band. By adding a three-cell NGD circuit while considering input and output matching at the input side of the MMIC amplifier, the group Delay variation is decreased by 78%. However, gain was also decreased by insertion of the multistage NGD circuit. In an attempt to avoid this decrease in gain, a one-cell NGD circuit was inserted into the feedback loop of the MMIC amplifier, and as a result, we were able to decrease the group Delay variation by 79%, with minimal gain deterioration.

  • Group Delay Equalized UWB InGaP/GaAs HBT MMIC Amplifier Using Negative Group Delay Circuits
    IEEE Transactions on Microwave Theory and Techniques, 2009
    Co-Authors: Ryo Ishikawa, Kazuhiko Honjo
    Abstract:

    A negative group Delay (NGD) circuit has been employed to equalize a group Delay variation in a broadband ultra-wideband (UWB) InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) amplifier. Using the NGD circuit, a part of a salient group Delay characteristic in the operation band of broadband amplifiers can be suppressed without an increase of the entire group Delay. The MMIC amplifier has a steep group Delay increase in the lower frequency region of the full-band UWB band (3.1-10.6 GHz) due to the sum of phase variations near the cutoff frequencies of the HBTs. The NGD circuit has been inserted to reduce this increase of the group Delay in the UWB band. By adding a three-cell NGD circuit while considering input and output matching at the input side of the MMIC amplifier, the group Delay variation is decreased by 78%. However, gain was also decreased by insertion of the multistage NGD circuit. In an attempt to avoid this decrease in gain, a one-cell NGD circuit was inserted into the feedback loop of the MMIC amplifier, and as a result, we were able to decrease the group Delay variation by 79%, with minimal gain deterioration.

Frank E. Van Vliet - One of the best experts on this subject based on the ideXlab platform.

  • frequency limitations of first order g_ m rc all pass Delay Circuits
    IEEE Transactions on Circuits and Systems Ii-express Briefs, 2013
    Co-Authors: Seyed Kasra Garakoui, Eric A. M. Klumperink, Bram Nauta, Frank E. Van Vliet
    Abstract:

    All-pass filter Circuits can implement a time Delay but, in practice, show Delay and gain variations versus frequency, limiting their useful frequency range. This brief derives analytical equations to estimate this frequency range, given a certain maximum allowable budget for variation in Delay and gain. We analyze and compare two well-known gm - RC first-order all-pass Circuits, which can be compactly realized in CMOS technology and relate their Delay variation to the main pole frequency. Modeling parasitic poles and putting a constraint on gain variation, equations for the maximum achievable pole frequency and Delay variation versus frequency are derived. These equations are compared with simulation and used to design and compare Delay cells satisfying given design goals.

  • Phased-array antenna beam squinting related to frequency dependency of Delay Circuits
    2011 41st European Microwave Conference, 2011
    Co-Authors: Seyed Kasra Garakoui, Eric A. M. Klumperink, Bram Nauta, Frank E. Van Vliet
    Abstract:

    Practical time Delay Circuits do not have a perfectly linear phase-frequency characteristic. When these Delay Circuits are applied in a phased-array system, this frequency dependency shows up as a frequency dependent beam direction (“beam squinting”). This paper quantifies beam squinting for a linear one-dimensional phased array with equally spaced antenna elements. The analysis is based on a (frequency-dependent) linear approximation of the phase transfer function of the Delay circuit. The resulting relation turns out to be invariant for cascaded cells. Also a method is presented to design time-Delay Circuits to meet a maximum phased-array beam squinting requirement.

  • ISCAS - Time Delay Circuits: A quality criterion for Delay variations versus frequency
    Proceedings of 2010 IEEE International Symposium on Circuits and Systems, 2010
    Co-Authors: Seyed Kasra Garakoui, Eric A. M. Klumperink, Bram Nauta, Frank E. Van Vliet
    Abstract:

    This paper shows that the group Delay of a Delay circuit does not give sufficient information to predict the Delay vs. frequency. A new criterion (f ϕ=0 ) is proposed that characterizes the Delay variations over a specified frequency range. The mathematical derivation of f ϕ=0 for a single Delay block and a cascade of Delay blocks is shown. As examples the criterion is applied to the design of an RC and LC Delay block. Delay predictions based on f ϕ=0 compared with simulation results, showing reasonable agreement.

  • Time Delay Circuits: A quality criterion for Delay variations versus frequency
    Proceedings of 2010 IEEE International Symposium on Circuits and Systems, 2010
    Co-Authors: Seyed Kasra Garakoui, Eric A. M. Klumperink, Bram Nauta, Frank E. Van Vliet
    Abstract:

    This paper shows that the group Delay of a Delay circuit does not give sufficient information to predict the Delay vs. frequency. A new criterion (fφ=0) is proposed that characterizes the Delay variations over a specified frequency range. The mathematical derivation of fφ=0 for a single Delay block and a cascade of Delay blocks is shown. As examples the criterion is applied to the design of an RC and LC Delay block. Delay predictions based on fφ=0 compared with simulation results, showing reasonable agreement.