Libe Mori

University of the Basque Country | UPV/EHU

Determining the origin and nature of the possible instabilities is key for an effective elimination of the unstable dynamics in multistage power amplifier design. In this work, a novel technique is proposed to provide a quantitative metrics that serves to locate and categorize the sensitive sections of the amplifier at which the unstable dynamics c...

Odd-mode parametric oscillations are a common cause of malfunctioning in power amplifiers. A very typical example of odd mode oscillation is the showing up of a spurious component at the fundamental frequency divide-by-two for some input power values. In this paper, a less known instability of odd-mode nature is analyzed. It occurs at the fundament...

The term pole-zero identification refers to obtaining the poles and zeros of a linear (or linearized) system described by its frequency response. This is usually done using optimization techniques (such as least squares, maximum likelihood estimation, or vector fitting) that fit a given frequency response of the linear system to a transfer function...

This article proposes an efficient method for the calculation of the stabilization parameters in RF power amplifiers operating in periodic large-signal regimes. Stabilization is achieved by applying the principles of linear control theory for periodic linear time-varying (PLTV) systems. A numerical method is proposed to obtain the harmonic transfer...

Understanding the nature of potential instabilities is indispensable for the stabilization of power amplifiers (PAs). Pole-zero identification is one of the techniques that can be used to determine the stability of a design in large-signal operations. In this work, the possible presence of poles at the fundamental frequency linked to the long-term...

Pole-zero identification is becoming a standard for the stability analysis of microwave power amplifiers. In this work we present the recent advances in the field that are driven by the use of Vector Fitting algorithms as identification tool. A residue analysis derived from a partial fraction representation of the transfer function is used to quant...

Low-frequency resonances with low stability margins affect video bandwidth characteristics of power amplifiers. In this paper, a nonconnectorized measurement technique is presented to obtain the low-frequency critical poles at internal nodes of a hybrid amplifier. The experimental setup uses a high-impedance probe connected to a vector network anal...

The presence of critical resonances in microwave power amplifiers has a negative impact on its behavior and performance. These critical resonances are usually predicted from pole-zero stability simulations. In this paper, a different and less demanding approach for the circuit designer is proposed. It is based on performing noise simulations of the...