R. Quere

40-GHz/150-ns versatile pulsed measurement system for microwave transistor isothermal characterization

A versatile pulsed I(V) and 40-GHz RF measurement system is described with all the know-how and methods to perform efficient, safe, and reliable nonlinear transistor measurements. Capability of discrimination between thermal and trapping effects with a pulse setup is demonstrated. Capture and emission constant times of trapping effects are measured. A method to electrically measure the thermal resistance and capacitance of transistors with a pulse setup is proposed.

A general program for steady state, stability, and FM noise analysis of microwave oscillators

Two novel algorithms are presented for nonlinear autonomous circuit CAD. In the first, a symbolic simulator is used to calculated the possible oscillation frequencies of the circuit, and the high-level behavior of the oscillator is determined by the harmonic balance method extended to autonomous circuits. The second algorithm is based on the conversion matrix method, which allows simulation of nonlinear microwave oscillator phase and amplitude noise spectra with linear and nonlinear correlated noise sources.<<ETX>>

A unified approach for the linear and nonlinear stability analysis of microwave circuits using commercially available tools

For the first time, an exhaustive linear and nonlinear stability analysis of multi-transistor MMIC circuits is presented. A key point of the proposed stability analysis lies in that it can be easily implemented on any CAD package. Our straightforward and powerful approach allows both linear and nonlinear stability analysis of any complex circuit submitted or not to large RF signals. Following our novel approach, a MMIC HBT power amplifier was analyzed. Division frequency phenomena and spurious oscillations were detected by simulations and confirmed by measurements.

Joint optimization of the power-added efficiency and the error-vector measurement of 20-GHz pHEMT amplifier through a new dynamic bias-control method

This paper presents a method for the optimization of the power-added efficiency (PAE), as well as the error-vector measurement (EVM) of a 20-GHz power amplifier (PA) applied in this case to the M quadrature and amplitude modulations. A first key point lies in that both input and output biasing voltages of the solid-state power amplifiers (SSPAs) are dynamically controlled according to the RF power level associated with the symbol to be transmitted. The leading idea is that the dynamic biasing control is designed and implemented to keep fixed amplitude (AM/AM) and phase (AM/PM) conversion values, while the RF input power level changes. The power gain of the PAs can then be dynamically tuned to a fixed power gain corresponding to the compression gain behavior for which the PAE is optimum at low-, medium-, and high-input RF power levels. As a main consequence, PAE performances can be drastically improved as compared to classical backoff solutions and optimized while keeping a very good EVM. A Ka-band hybrid amplifier has been realized using an 8/spl times/75 /spl mu/m power pseudomorphic high electron-mobility transistor. The proposed linearization technique is validated by comparisons between measured PAE and EVM on the SSPA when a fixed and controlled bias are used.

Linear and nonlinear FET modeling applying an electromagnetic and electrical hybrid software

A new approach is presented in this paper to help the modeling of complex active microwave devices like field-effect transistors. This hybrid method couples an electromagnetic three-dimensional simulator to characterize the extrinsic part and a circuit software to introduce the contribution of the component intrinsic part. The interests of such approach are diverse and are discussed in this paper. Theoretical linear and nonlinear results are compared with measurements and show good agreements.

Modeling of trap induced dispersion of large signal dynamic Characteristics of GaN HEMTs

We propose here a non-linear GaN HEMT model for CAD including a trapping effects description consistent with both small-signal and large-signal operating modes. It takes into account the dynamics of the traps and then allows to accurately model the modulated large signal characteristics that are encountered in telecommunication and radar signals. This model is elaborated through low-frequency S-parameter measurements complementary to more classical pulsed-IV characterizations. A 8×75μm AlInN/GaN HEMT model was designed and particularly validated in large-signal pulsed RF operation. It is also shown that thermal and trapping effects have opposite effects on the output conductance, thus opening the way for separate characterizations of the two effects.

An improved CAD oriented FET model for large-signal and noise applications

A novel equivalent circuit for FETs, based on a two region, ohmic and velocity saturated, description of the channel is proposed. The model has a topology close to the main physical phenomena which determine the device behaviour, thus the parameters can be deduced in a natural way. Analytical determination for the new electrical model elements holds so that there is no increase in the extraction cost. The model applied to commercial FETs and HEMTs demonstrates an improved accuracy over the classical models and, at the same time, opens interesting perspectives in the fields of nonlinear and noise electrical modelling for CAD.<<ETX>>

New design method of non-uniform distributed power amplifiers. Application to a single stage 1 W PHEMT MMIC

A new design methodology of non-uniform distributed power amplifiers is reported in this paper. This method is based on analytical expressions of the optimum input and output artificial lines making up the non-uniform distributed power amplifier. These relationships are based on the optimum load line requirement for power operation. To validate the proposed design methodology, a non-uniform distributed power amplifier has been manufactured at the TriQuint Semiconductor foundry using a 0.25 /spl mu/m power PHEMT process. This single stage MMIC amplifier is made of six non-uniform cells and demonstrates 1 W output power with 7 dB associated gain and 20% PAE over multi-octave bandwidth.

A non-quasi-static model of GaInP/AlGaAs HBT for power applications

A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presented. Besides thermal effects, this model includes also two transcapacitances to take into account the Non-Quasi-Static (NQS) effects. It is shown that contrary to a Quasi-Static (QS) one, this model allows to predict accurately the behavior of the device in the whole power range as well as a broad frequency band.

The Spectral Balance: A General Method for Analysis of Nonlinear Microwave Circuits Driven by Non-Harmonically Related Generators

A very wide class of non-linear microwave circuits including mixers, oscillators (with their noise generators) and multitone amplifiers, are driven by non-harmonically related signals, and involve very far or closely-spaced frequency components. In this paper an efflcient method is proposed to perform the balance of non-linear circuits driven by non-harmonically related input signals. It may be named: The spectral balance.