Non-linear distortion analysis of Ka BAND MMIC’s under single-tone, TWO-TONE and NPR excitations.

An experimental comparative study of nonlinear distortion effects in 26-40 GHz frequency band on telecommunication MMIC’s subject to constant wave single-tone, two-tone and NPR excitations are presented in this paper. The study is performed using a wave-guide based power measurement setup previously developed and recently fully automated to allow very accurate analyses about nonlinear behaviour of PHEMT SSPA’s. The purpose of these studies is to determine the MMIC linearity performances at 29 GHz versus bias conditions. But also to improve the PHEMT technological parameters and the circuits designs as a function of the analyses

High Power Performances of AlGaN/GaN HEMTs On Sapphire Substrate At F=4GHz

The high potential at microwave frequencies of AlGaN/GaN HEMTs on sapphire substrate for power application has been demonstrated in this paper. An output power density close to 5W/mm has been measured on a 2x25x0.5µm² HEMT on sapphire substrate. This result is very interesting because the devices have not been passivated. At present time, it is the best power result in Europe on this substrate

Radiation pattern measurements of an integrated TEM horn antenna

International audienceA TEM horn antenna is integrated with a uni-travelling-carrier photodiode. Its radiation pattern is measured from 280 to 540 GHz thanks to a 1.55 μm photomixing set-up and a sub-harmonic mixer. The direction the main lobe shifts to a lower incidence when the frequency is increased

An interferometric scanning microwave microscope and calibration method for sub-fF microwave measurements

International audienceWe report on an adjustable interferometric set-up for Scanning Microwave Microscopy. This interferometer is designed in order to combine simplicity, a relatively flexible choice of the frequency of interference used for measurements as well as the choice of impedances range where the interference occurs. A vectorial calibration method based on a modified 1-port error model is also proposed. Calibrated measurements of capacitors have been obtained around the test frequency of 3.5 GHz down to about 0.1 fF. Comparison with standard vector network analyzer measurements is shown to assess the performance of the proposed system

Non linear microwave characterization and modelization of carbon nanotube FETs

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Sub-10 nm-scale capacitors and tunnel junctions measurements by SMM coupled to RF interferometry

International audienceWe have developed an adjustable Interferometer combined to a Scanning Microwave Microscopy (ISMM) to characterize the impedance of thousands of nanocapacitors. The adjustable interferometer allows the choice of the interference frequency within ± 50 MHz as well as the choice of the impedance range where the interference occurs. Calibration is investigated using metal-insulating-semiconductor capacitances. The ISMM allows quantitative characterization of tiny capacitors with size reaching sub-10 nm and capacitance value around the aF with a limit of resolution of about 0.5 aF at 7.8 GHz. A water meniscus parasitic capacitance is introduced to explain the discrepancy between measured and theoretical values over the 5 to 100-nm nanodot diameter range. The ISMM allows also measuring tunnel junctions made with very thin Al2O3 dielectric layers