Colombo R. Bolognesi

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We report the large-signal performance of high electron mobility transistors (HEMTs) fabricated on GaN- and AlN-capped AlInN/GaN epilayers grown on semi-insulating SiC substrates. Large-signal measurements at 10 and 40 GHz are presented with both gate and drain dynamic loadlines to clarify the factors limiting the high-power performance. Devices fabricated(More)
We report the first 94-GHz (W-band) large-signal performance of AlInN/GaN high-electron-mobility transistors (HEMTs) grown on high-resistivity silicon (111) substrates. A maximum output power density of 1.35 W/mm and peak power-added-efficiency of 12% are measured at 94 GHz. The devices exhibit a dc maximum current drain density of 1.6 A/mm and a peak(More)
We characterize the microwave loss in coplanar waveguides (CPWs) on AlGaN/GaN HEMT buffer layers on high-resistivity silicon (HR-Si) substrates, up to 110 GHz. To our knowledge, this is the first broadband characterization of CPWs on GaN-on-Si. Conventional CPWs on commercially available AlGaN/GaN on HR-Si HEMT layers show a loss as low as 0.8 dB/mm at 110(More)
We report the large-signal load-pull characterization of InP/GaAsSb double heterojunction bipolar transistors (DHBTs) with f<sub>T</sub> and f<sub>MAX</sub> cutoff frequencies as high as 380 and 320 GHz, respectively. Measurements were performed at 40 GHz in a passive load-pull system to characterize the output power and power-added-efficiency (PAE)(More)
A new W-band active load-pull system is presented. It is the first load-pull system to implement a 94 GHz load by means of an active loop exploiting frequency conversion techniques. The active loop configuration demonstrates a number of advantages that overcome the typical limitations of W-band passive tuners or conventional active open-loop techniques in a(More)
We report the fabrication and characterization of 30-nm-gate fully passivated AlInN/GaN high-electron mobility transistors (HEMTs) with cutoff frequencies <i>f</i><sub>T</sub> and <i>f</i><sub>MAX</sub> simultaneously exceeding 200 GHz at a given bias point. The current gain cutoff frequency does not vary significantly for 2.5 &lt;; <i>V</i><sub>DS</sub>(More)
We report a new generation of high-performance AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on high-resistivity Si (111) substrates. We map out small- and large-signal device performances against technological parameters such as the gate length and the source-drain contact separation. We report the first large-signal performance for a(More)
In this paper, a thorough evaluation of calibration residual uncertainty of on-wafer load-pull systems at millimeter-wave frequencies, with actual comparisons between real-time and non-real-time load-pull systems, is reported for the first time. Two figures of merit for uncertainty evaluation are taken into account, showing the differences between the two(More)
We report a single-stage InP-high-electron-mobility-transistor (HEMT) X-band low-noise amplifier (LNA) featuring an ultralow dc power consumption at room temperature. The LNA was fabricated with the ETH Zu&#x0308;rich 100-nm InP-HEMT MMIC coplanar waveguide process. When operated with a dc power consumption of only 0.6 mW, our LNA delivers a gain of 9.0(More)
We demonstrate InP/GaAsSb/InP double heterojunction bipolar transistors (HBTs) fabricated in a low-temperature planarization process based on a spin-on Teflon amorphous fluoropolymer interlevel dielectric with &#x03B5;<sub>r</sub> = 1.9 and a low dissipation factor. Devices with 0.3-&#x03BC;m-wide emitters show excellent junction characteristics, cutoff(More)