Luc Lapierre

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This work describes an analysis and design methodology for eliminating parametric oscillations in microwave power amplifiers. Large-signal stability analyses based on system pole-zero identification techniques are proposed to guide the design process towards a stable circuit. In order to demonstrate the proposed approach, parametric oscillations of a(More)
In this paper a two-stage 2-GHz GaN HEMT amplifier with 15-W output power, 28-dB power gain, and 70% power-added efficiency (PAE) is presented. The power stage is designed to operate under class F conditions. The driver stage operates under class F<sup>-1</sup> conditions and feeds the power stage with both fundamental and second harmonic components. The(More)
To assess the potential of the macroinvertebrate community for monitoring variation in the environmental quality of large rivers, the response of littoral macrobenthos in Lake Saint-François, a fluvial lake of the St Lawrence River (Québec) are described. First, the composition of total macroinvertebrate communities and important taxonomic groups as well as(More)
The concept of effective diffusion length, as a means to characterize diffusion losses in calculations of microwave breakdown in radio frequency (RF) devices with inhomogeneous electric fields, is discussed in detail with emphasis on geometrical situations where the inhomogeneity of the microwave electric field plays an important role for the breakdown(More)
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(More)
This paper presents a wideband ohmic shunt switch implemented on a coplanar waveguide (CPW). The switch is fabricated using a dielectric membrane with patterned metallic contacts that short the CPW line when it is electrostatically actuated. The switch has been extrapolated from measurements. It exhibits low insertion loss, good matching, high isolation(More)
Pure Valencia orange (Citrus sinensis) juices (64 samples) from Spain, Israel, Belize, Cuba, and Florida, harvested during two seasons (1996-1997 and 1997-1998), were analyzed for their carotenoid profiles. The detection of saponified carotenoid pigments has been achieved and quantitated using a photodiode array detection monitored at 350, 430, and 486 nm.(More)
Three methods for improved deresination of sulphite pulps were evaluated, namely, alkaline washing, enzyme treatment, and pulp fractionation. Alkaline washing appears to come at a high cost, because caustic is expensive and affects cellulose chain length, as indicated by lower viscosity of the pulps. Thus this is not a viable option for pulps that are(More)
This paper presents the first development of a space-borne power amplifier using the recently developed high breakdown, high Power HBT HB20S process of UMS. The inverse F class Hybrid Power Amplifier has been designed using intensive simulation methods developed at Alcatel Space for MMICs, allowing to reach very high performances without manual tuning. The(More)
This paper presents an accurate technique for the characterization of intermodulation noise in wide band multi carrier power amplifiers. Band limited pseudo noise stimuli which are generated by using a computer controlled arbitrary waveform generator (AWG) connected to an I/Q modulator drive the input of the amplifier under test ( AUT ). The complex(More)