A new criterion for linear 2-port stability using a single geometrically derived parameter

Edwards, M.L.; Sinsky, J.H.

doi:10.1109/22.179894

Cited by 317 publications

(185 citation statements)

References 5 publications

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“…These special cases lead to the extra conditions that must be satisfied [1]- [6]. Another recent advance, well worth noting to students, is the so-called stability factor [9].…”

Section: Discussionmentioning

confidence: 99%

Teaching Microwave Amplifier Design at the Undergraduate Level

Eccleston

2004

IEEE Trans. Educ.

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Abstract-Many textbooks on the subject of microwave amplifier design contain redundant material that may overload and confuse a student confronting microwave amplifiers for the first time. Some topics such as unilateral gain and unilateral design are often not necessary in this day of personal computing where exact gain and gain circle calculations can easily be used. Stability circles can be used to both identify allowable values of source and load reflection coefficients for the transistor and ascertain whether or not the transistor is unconditionally stable. By eliminating redundant topics and emphasizing the dual role of stability circles, instructors are able to effectively teach undergraduate students in a relatively short time design methods for narrow-band low-noise amplifiers, both single-stage and multistage, which employ either conditionally or unconditionally stable transistors.

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“…These special cases lead to the extra conditions that must be satisfied [1]- [6]. Another recent advance, well worth noting to students, is the so-called stability factor [9].…”

Section: Discussionmentioning

confidence: 99%

Teaching Microwave Amplifier Design at the Undergraduate Level

Eccleston

2004

IEEE Trans. Educ.

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“…If this value can be estimated, the two factors  and µ' [39] (instead of k LS and  LS ) may be especially useful to predict the possible instability under a particular  max . This is because at each perturbation frequency f, they will provide the minimum magnitudes of the sideband reflection coefficients (| l | and | u |) from which negative resistance (at the opposite sideband) will be obtained.…”

Section: Potential Instability Analysis Under Mismatch Effectsmentioning

confidence: 99%

“…Note that a single condition can only be used in terms of the µ factor [39]. The computation of conditions (21) is directly carried out by commercial software when the new scattering type matrix, calculated with the two circuits in Fig.…”

Section: Potential Instability Analysis Under Mismatch Effectsmentioning

confidence: 99%

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Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Suárez

Ramírez

Sancho

2014

IEEE Trans. Microwave Theory Techn.

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1 Abstract -Novel criteria are presented for small-and large-signal stability analysis of microwave circuits under output mismatch effects. They are based on concepts from bifurcation theory, which enable the derivation of general equations for the stability boundaries that depend on the termination load. The boundary calculation does not require any optimization of the circuit parameters. Instead, it is based on the direct calculation of an admittance function obtained through circuit linearization about either the dc solution, in the small-signal stability analysis, or the periodic solution, in the large-signal one, with low computational cost. As will be demonstrated both with homotopy and bifurcation concepts, the Hopf locus obtained in this way delimits a stable region and a potentially unstable one. In a large-signal stability analysis, the sidebands that influence the stability properties are identified, which depend on the particular amplifier topology and its filtering effects. The stability boundaries are then calculated with the conversion matrix approach for all load impedance values at the relevant harmonic and sideband frequencies. For the derivation of absolute stability conditions, a new scattering type matrix is proposed describing the circuit response from the output reference plane with respect to the two sidebands about the input carrier. The new methodologies and formulations have been validated by independent simulations using pole-zero identification, and by measurements.

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“…This is done considering three virtual ports, corresponding to the three mismatched sidebands, with the rest of harmonics and sideband frequencies constituting an inner tier. Under fulfillment of an equivalent of the Rollet's proviso [6] established in [4], the potential instability can be detected at PA output reference plane, using three large-signal equivalents of the stability factor (m) [7], defined in [4]. These large-signal m factors depend on the reflection coefficient G o at f in , the perturbation frequency f, and the input power P in .…”

Section: Introductionmentioning

confidence: 99%

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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A new criterion for linear 2-port stability using a single geometrically derived parameter

Cited by 317 publications

References 5 publications

Teaching Microwave Amplifier Design at the Undergraduate Level

Teaching Microwave Amplifier Design at the Undergraduate Level

Stability Analysis of Power Amplifiers Under Output Mismatch Effects

Prediction of odd-mode instabilities under output mismatch effects

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