Daniel Roques

A Novel Experimental Noise Power Ratio Characterization Method for Multicarrier Microwave Power Amplifiers

The linearity characterization of multicarrier power amplifiers in terms of Noise Power Ratio (NPR) is now well adopted. The use of an analog band pass noise source with a notch in the center bandwidth is currently used for this purpose. We present in this paper a novel NPR measurement technique based on a numerical generation of a gaussian noise. This experimental noise generation is similar to the technique used in non linear circuit level or system level simulations using the envelope transient technique. The measurement principle is based on the use of a baseband arbitrary waveform generator (AWG) and an upconverter chain from baseband to L or S band. The large signal Noise stimuli drive the amplifier under test. The output signal of the amplifier is downconverted back to baseband and the resulting complex envelope is recorded with a sampling scope and computed for NPR extraction. A comparison of NPR measurements obtained with our method and with the conventional analog noise source technique is presented. Other possible applications of our measurement system are also mentioned and emphasize the capabilities of the proposed characterization tool.

A new concept to cancel insertion phase variation in MMIC amplitude controller

A concept which keeps a very low insertion phase variation in an analog monolithic microwave IC (MMIC) amplitude controller is presented. This new approach, applicable to dual-gate FET (DGFET) variable-gain amplifiers, is to connect an active variable load to the second gate of the DGFET. This load makes use of a cold FET (with Vds=0 V) whose impedance varies depending on the amplitude command of the circuit. Then, the cold FET compensates the insertion phase change introduced by the DGFET attenuation control over a wide dynamic range. Based on this principle, a C-band GaAs MMIC attenuator for active antenna application has been designed. The phase variation versus gain is always lower than +or-2 degrees over a 20-dB gain/attenuation range.<<ETX>>

GaAs MMIC control functions for 3.7-4.2 GHz band active antenna

This paper describes the realization of gain and phase control function in GaAs microwave monolithic integrated circuit (mmic.). The measured performances are successfully compared with simulation results. The attenuator uses a dual-gatefet in order to adjust the level of the transmitted signal. The obtained dynamic range is 27 dB. The phase-shifter is made up of T and π networks connected in series and makes use of the capacitance variation of Schottky diodes to change the transmission phase. The phase shift reaches 115° at its maximum. Both circuits have been developed for a C-band beam forming network project for space communications.RésuméCet article décrit la réalisation de fonctions de contrôle de gain et de phase en technologie monolithique hyperfréquence GaAs. Les caractéristiques mesurées sont comparées aux résultats de simulation avec succès. L’atténuateur utilise untec double-grille afin d’ajuster le niveau du signal transmis. On obtient ainsi une dynamique de 27 dB. Le déphaseur est constitué par la mise en série de réseaux T et π et utilise la variation de capacité de diodes Schottky pour changer la phase du signal transmis. Le déphasage obtenu atteint 115° au maximum. Ces deux circuits ont été développés pour des réseaux de formation de faisceaux étroits dans la bande de 3,7 à 4,2 GHz pour télécommunications spatiales.

Ka-band coplanar low-noise amplifier design with power PHEMTs

The design of a coplanar low-noise amplifier (LNA) is presented in this paper. Pseudomorphic high electron mobility transistors (PHEMTs), optimized for power applications, are used in order to evaluate the potentiality of this technology for mixed-mode applications. The three stages amplifier noise figure is lower than 2.6 dB on the 27 - 31 GHz frequency band with a 20 dB power gain.

A Very Flat Variable Gain Amplifier MMIC for C-Band Satellite Receiver

This paper describes the design, the realization, and the performance of two versions of an analog C-band GaAs variable gain amplifier module suitable to application in C-band satellite receiver. This modules uses the ability of the Dual-Gate MESFET to provide variable gain. The highest obtained dynamic control range is 30 dB with very flat gain response within 3-5 GHz frequency range. Input and output return losses are always better than 15 dB and the phase variation versus gain lower than 10 degrees over a 20 dB gain/attenuation range. Two wafers of both versions were processed by THOMSON/DAG GaAs foundry using a 0.5 ¿m gate length technology. The overall manufacturing RF-yields are 45% and 60% for the two versions presented.

A Review of Advanced Microwave Equipment on the Experimental Satellite Stentor

The explosion of the telecommunication market is also impacting the space segment and the satellite payloads. All over the world, the industry is making strong efforts to reduce cost and delivering time for commercial programs, while decreasing hardware mass and increasing overall performance. Following American and Japanese initiatives, the French agencies (CNES, France Télécom. DGA) have joined their efforts to promote new and competitive technologies by implementing a technological program: STENTOR. This ambitious project aims at flying several advanced concepts which are described here for what concerns the microwave sub-systems.

Optimal Design of Solid State Multicarrier Power Amplifiers

Designing power amplifier for modern comunication systems is a challenging topic. A new design methodology for multicarrier power amplifiers (MCPA) is described which is based on an objective optimality criterion as to linearity and power consumption of amplifier building blocs. Amplifier design results are presented which shows the effectiveness of the methodology.

A 2 watts Ku-band class AB MMIC amplifier

The aim of this paper is to present the design and measurements of a Ku-band class AB power amplifier. This two stage amplifier, designed by ALCATEL and manufactured by THOMSON foundry service with HP07 process, works between 10.7 et 12.75 GHz. 11 dB gain is obtained with 33 dBm output power and a power added efficiency better than 27 % at 11.75 GHz.

Ku-Band MMIC's for Space-Borne Active Antenna

A full set of Ku-Band monolithic integrated circuits designed for a spatial telecommunication active antenna is presented. Low Noise Amplifier, Medium Level Amplifier, Mixer, Attenuator and Digital Phase-Shifter are detailed and the measured results are discussed. This is completed with the design and simulation of Digital and Analog Phase-Shifter whose processing is in progress.

A process-dependent worst-case analysis for MMIC design based on a handy MESFET simulator

The design of inexpensive MMIC modules implies a practical use of worst-case analysis. A reliable equivalent circuit model based on the unavoidable dispersion of uncorrelated technological parameters is proposed. The method relies on a convenient MESFET simulator which provides the DC, RF and noise parameters for any bias conditions. The input data are geometrical or electrical information readily available to the designer. The results of using the proposed model are compared with experimental data from several GaAs MMIC manufacturers. The model was also successfully applied to the design of a monolithic C-band amplifier. The forecasts of the worst-case analysis are compared with the experimental results for this amplifier. >