Temperature dependent analytical model for submicron GaAs-MESFET

MESFET are used in circuitsof gigahertz frequencies as they are based on gallium arsenide (GaAs) having electron mobility six times higher than that of silicon. An analytical model simulating different device current-voltage characteristics, i.e., output conductance and output transconductance of a 0.3μm gate MESFET with temperature dependence is proposed. The model is validated by comparing the results of the proposed model and those of the numerical simulation. The parameter values are computed using an intrinsic MESFET of two-dimensional geometry. In this work, the distribution of different output loads for varied applied voltages is considered. Simulation results obtainedunder temperature variation effectsfor load distribution and applied driven voltage variation are considered. The RMS and average errors between the different models and GaAs MESFET simulations are calculated to evidence the proposed model accuracy. This was demonstrated by a good agreement between the proposed model and the simulation results, which are found in good agreement. The simulation results obtained under temperature variations were discussed and found to complement those obtained in the literature. This clarifies the relevance of the suggested model analytical.

STUDY ON THE INFLUENCE OF ELECTROPHYSICAL CHARACTERISTICS ON THE PARAMETERS OF COMPACT MODELS OF THE COMPONENTS USED IN RADIO FREQUENCY MONOLITHIC INTEGRATED CIRCUITS

In this paper we demonstrate the results of the study on how the geometric parameters effect the model parameters of passive and active components. As we found out, the substrate thickness has the greatest influence on the equivalent circuit model parameters of passive components. Paper demonstrates the influence of the gate length and the gate recess depth on the parameters of small-signal model of the MESFET. The obtained dependences are presented for the MIM capacitor model, inductor model and GaAs MESFET model.

Fuzzy Logic based Method for the Extraction of Extrinsic and Intrinsic Elements of Microwave Transistors

In this paper we propose a new method for the extraction of extrinsic and intrinsic elements for microwave transistors based on a fuzzy logic architecture. The proposed technique uses the experience of the designer in order to extract and optimize in a smart way only the electrical elements required for an accurate multibias scattering parameters prediction. We tested our model with a GaAs MESFET 6 x 120 um and a Al GaAs P-HEMT 6 x 15 um device. It has been demonstrated that the proposed method is more accurate than the conventional one, evaluated with the previous technologies. The global behavior of the transconductance (gm) and gate to source capacitance (Cgs) measured with this technique agrees with the physical properties of the above mentioned technologies. Another advantage of this method is that the conventional “Cold-FET” configurations (Vds=0V) are not required, which warrant the reliability of the microwave transistor. The methodology presented in this work can be used in the RF circuit design industry as a first step for an accurate transistor characterization.

Improvement of Carrier Power to Third-Order Intermodulation Distortion Power Ratio for a Power Amplifier at 5.25 GHz using LINC Method

Introduction:This paper focuses on improving the power amplifier linearity for wireless communications. The use of a single branch of a power amplifier can produce high distortion with low efficiency.Method:In this paper, the Linear Amplification with Nonlinear Components (LINC) technique is used to improve the linearity and efficiency of the power amplifier. The LINC technique is based on converting the envelope modulation signal into two constant envelope phase-modulated baseband signals. After amplification and combining the resulting signals, the required linear output signal is obtained. To validate the proposed approach, LINC technique is used for linearizing an amplifier based on a GaAs MESFET (described by an artificial neural network Model).Conclusion:Good results have been achieved, and an improvement of about 40.80 dBc and 47.50 dBc respectively is obtained for the Δlower C/I and Δupper C/I at 5.25 GHz.

Effect of Mobility on (I-V) Characteristics of Gaas MESFET

<p class="Titre51"><span lang="EN-US">We present in this paper an analytical model of the current–voltage (I-V) characteristics for submicron GaAs MESFET transistors. This model takes into account the analysis of the charge distribution in the active region and incorporate a field depended electron mobility, velocity saturation and charge build-up in the channel. We propose in this frame work an algorithm of simulation based on mathematical expressions obtained previously. We propose a new mobility model describing the electric field-dependent. The predictions of the simulator are compared with the experimental data [01] and have been shown to be good.</span></p>