Systematic Approach to the Stabilization of Multitransistor Circuits

Ayllon, Natanael; Collantes, J.M.; Anakabe, A.; Lizarraga, Ibone; Soubercaze-Pun, Geoffroy; Forestier, S.

doi:10.1109/tmtt.2011.2155667

Cited by 52 publications

(93 citation statements)

References 20 publications

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“…Pole-zero identification [8][9][10] would be applicable to detect the odd-mode instabilities under mismatch effects. However, the odd-mode excitation must be preserved as otherwise the impedance at sideband frequencies would be ill represented with a constant G o .…”

Section: I D E T E C T I O N O F O D D -M O D E I N S T a B I L Imentioning

confidence: 99%

“…This must be complemented with a local-stability analysis, such as pole-zero identification [8][9][10] to distinguish between stable and unstable regions. It will be sufficient to apply this local-stability analysis to representative points in the various regions separated by the loci.…”

Section: I D E T E C T I O N O F O D D -M O D E I N S T a B I L Imentioning

confidence: 99%

“…This is done with a simple graphical technique that takes advantage of the bounded nature of r o and f o . The perturbation frequency f is swept between 0 and f in [8][9][10] and, for each f, a double sweep is performed in r o , f o , so as to cover the entire Smith chart. For each triplet f, r o , f o , the total admittance Y T is calculated as the ratio between the current delivered by the small-signal source and the voltage across its terminals There are no crossings of the negative real semi-axis, so there is no oscillation boundary within the Smith chart.…”

Section: A) Incommensurable Oscillationmentioning

confidence: 99%

“…This is due to the 1808 phase shift between different amplifier branches, which gives rise to a virtual short circuit at mf in + f at the circuit output. There is a cancellation of the possible unstable poles with right-hand side (RHS) zeroes [8][9][10], so the instability cannot be detected from the circuit output plane. On the other hand, the impedance terminations at mf in + f will not have any impact on the potential instability, which will only depend on the terminations at mf in .…”

Section: Introductionmentioning

confidence: 99%

“…The boundary is calculated in terms of the termination G o and traced in the Smith chart. Stable and unstable regions are distinguished through pole-zero identification [8][9][10], applied to representative points in the distinct regions separated by the boundary.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Prediction of odd-mode instabilities under output mismatch effects

Rodríguez

Terán

Lucio

2017

Int. J. Microw. Wireless Technol.

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Prediction of odd-mode instabilities under output mismatch effects almudena sua ' rez, franco rami 'rez and sergio sancho A methodology is presented to predict odd-mode instability in power amplifiers under output mismatch effects, as in the case of amplifiers connected to an antenna. This kind of instability is often observed in multi-device configurations, due to their symmetry properties. Unlike the single-ended situation, there is a cancellation of odd multiples of the oscillation frequency at the circuit output, so there is no impact of the load-impedance values at the sideband frequencies. The odd-mode instability only depends on the impedance terminations at the fundamental frequency and its harmonic terms, and can only be detected within the circuit unstable loop, instead of the antenna-connection terminals. The possible unstable modes are related with the eigenvectors of an outer tier conversion matrix accounting for the symmetry properties of the circuit topology. Under sufficient low-pass filtering of the amplifier output network, the analysis parameters can be limited to the magnitude and phase of the reflection coefficient at the fundamental frequency. This analysis involves a computationally efficient graphical technique to detect potential instabilities and a bifurcation-detection method to determine the instability boundaries in the Smith chart. The two main types of instability from periodic regime are considered, respectively associated with incommensurable and subharmonic oscillations. Results have been validated through pole-zero identification and experimental measurements.

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Section: I D E T E C T I O N O F O D D -M O D E I N S T a B I L Imentioning

confidence: 99%

Section: I D E T E C T I O N O F O D D -M O D E I N S T a B I L Imentioning

confidence: 99%

Section: A) Incommensurable Oscillationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Prediction of odd-mode instabilities under output mismatch effects

Rodríguez

Terán

Lucio

2017

Int. J. Microw. Wireless Technol.

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Radiofrequency Stability Analysis

Suárez

2012

Wiley Encyclopedia of Electrical and Electronics Engineering

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This article will provide essential concepts for a basic understanding of the nonlinear dynamics of microwave circuits, so that a designer may distinguish between different types of steady‐state solutions, identify instability problems, and comprehend mechanisms for instability. The aim is to increase a designer's awareness and knowledge on what can go on in a nonlinear circuit. The harmonic‐balance method will be briefly outlined, with emphasis on the need to combine this method with a stability analysis to ensure the physical existence of any solution obtained. The article will cover the stability analysis of microwave circuits in small‐ and large‐signal regimes. The main approaches for stability analysis will be presented and compared, from the most familiar ones, Rollet factor and stability circles, to very recent and efficient techniques, such as pole‐zero identification. Another problem covered will be the abrupt change in the solution observed when a parameter, such as a bias voltage or input power, is modified continuously.

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Joint RF and large-signal stability optimization of MMIC power combining amplifiers

Ayllon

Collantes

Anakabe

et al. 2013

Int. J. Microw. Wireless Technol.

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In this paper, authors report on an enhanced approach for the design of monolithic microwave integrated circuit (MMIC) power combining amplifiers. Commonly used techniques for the stabilization of such circuits are empirical and too conservative. This leads very often to a non-desired degradation of the radio frequency (RF) performances that are inherent to the physical properties of such stabilization networks at the fundamental frequency of operation. The methodology proposed here is based on the use of large-signal optimization processes that combine RF and stability analyses from the early stages of the design. This approach results in an improvement of the RF performances while sufficient stability margins are preserved. The optimization procedure is explained on a Ku-band MMIC power amplifier for space-borne communications.

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Systematic Approach to the Stabilization of Multitransistor Circuits

Cited by 52 publications

References 20 publications

Prediction of odd-mode instabilities under output mismatch effects

Prediction of odd-mode instabilities under output mismatch effects

Radiofrequency Stability Analysis

Joint RF and large-signal stability optimization of MMIC power combining amplifiers

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