Three-Terminal Junctions operating as mixers, frequency doublers and detectors: A broad-band frequency numerical and experimental study at room temperature

The frequency response of nanometric T- and Y-shaped three-terminal junctions (TTJs) is investigated experimentally and numerically. In virtue of the parabolic down-bending of the output voltage of the central branch obtained at room temperature under a push-pull fashion input, we analyze: the low-frequency performance (<1 MHz) of TTJs operating as mixers, their RF capability as doublers up to 4 GHz and detection at 94 GHz. Special attention is paid to the impedance matching and cut-off frequency of the measurement set-up. The numerical study is done by means of Monte Carlo simulations. We illustrate the intrinsic functionality of the device as frequency doubler or rectifier up to THz. The role of the width of the central branch on the highfrequency response is also explored, finding different cut-off frequencies for doubling and detection as a consequence of the diverse working principles of both mechanisms and the particular geometry of the TTJs.ROOTHz (FP7-243845

Temperature Effect on DC and Equivalent Circuit Parameters of 0.15-μm Gate Length GaN/SiC HEMT for Microwave Applications

Thermal characterizations and modeling have been carried out on a 0.15 μm × (4 × 50) μm gate GaN-/SiC-based high-electron-mobility transistor varying the temperature from -40 °C to 150 °C and the frequency up to 50 GHz using on-wafer measurements. The thermal behavior of the dc parameters along with thermal resistance estimation and the equivalent circuit parameters along with cutoff and maximum frequencies were analyzed and reported using a single device. The temperature coefficients of these parameters were presented and deduced the influence of thermal effects on device parameters. These results are important for the circuit designer for future advancement and design optimizations of GaN-based monolithic microwave ICs.</p

AlGaN/GaN HEMT on (111) single crystalline diamond

AlGaN/GaN HEMTs have been fabricated directly on (111) oriented single crystal diamond with 1.3 x 10(13) cm(-2) channel sheet charge density and 731 cm(2)/Vs mobility. 0.2 mu m gate length devices showed 0.73 A/mm maximum drain current density and f(T) and f(max) cutoff frequencies of 21 and 42 GHz