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A self-switching diode (SSD) is based on an asymmetric nanochannel. The SSD is fabricated by tailoring the boundary of a narrow semiconductor channel to break its symmetry. An applied voltage V not only changes the potential profile along the channel direction but also either widens or narrows the effective channel width, depending on its sign. This results in a strong nonlinear current-voltage I-V...
This work presents an experimental study of the low-frequency dispersion which impairs the performance of microwave active solid state devices. By exploiting low-frequency large-signal excitations (< 10 MHz), the dynamic behaviour of the drain-source current generator is highlighted as function of the operating bias condition and frequency. In order to assess the capability of the proposed investigation...
Recently, new behavioral model formulations have been introduced to describe transistor non-linear behavior. In addition to providing an alternative approach to modeling nonlinear behavior in CAD tools based directly on measured data, they also provide for the possibility of extending analytical circuit analysis to the domain of non-linear circuits. An important example would be an analytical means...
Wideband amplifiers for the next generation of T/R modules in future active array antennas are realized as monolithically integrated circuits (MMICs) on the basis of novel InAlGaN/GaN high electron mobility transistor (HEMT) structures. All designs are realized in microstrip transmission line technology. The wideband amplifier MMICs operate up to a frequency of 18GHz. A number of measurements have...
The paper introduces a new pulsed measurement system for the characterization of thermal and charge trapping effects in compound semiconductor III-V FETs. Minimization of reflections are obtained by pulse generation in a 50 Ω environment and separation between DC and AC path guarantees no variations of the average voltage values of pulses. Both GaAs- and GaN-based FETs are characterized and some differences...
On-chip transmission lines in silicon technologies suffer from the low-resistivity substrate and geometric limitations imposed by layout and metal density design rules. In this paper, we demonstrate that 3D coplanar strip (3DCPS) transmission lines can be utilized to overcome both problems by taking advantage of the multiple metal layers available. A test chip was designed to validate the concept...
High-resistivity Silicon substrates, thanks to their low cost and large wafer diameter, could represent a viable solution for the high power GaN-based transistors realization, even if device thermal management optimization is necessary because of thermal conductivity limitations of Silicon. In this work, a comparison between LG=0.5μm GaN on Silicon HEMT devices fabricated in Coplanar Waveguide (CPW)...
This paper presents an improved 4-stage on-chip open loop resonator band pass filter (OLR-BPF) for 60 GHz millimeter-wave applications in 0.18 μm CMOS technology. The proposed on-chip BPF employs the folded open loop structure on patterned ground shields in first two stage and open-loop resonator in last two stages to improve the selectivity. By comparison between the electromagnetic (EM) simulations...
This paper proposes a method to improve the power consumption of dual-conduction class-C VCO. The dual-conduction class-C VCO has two pairs of cross-coupled transistors for low supply voltage operation. One is a main pair for the class-C operation, the other is an auxiliary pair for startup. The auxiliary pair continues to operate after the VCO starts class-C operation, which consumes additional power...
Manga is a five Nation (Germany, France, Italy, Sweden and United Kingdom) joint project realized by the European Defence Agency (EDA) which focuses on SiC substrates and a GaN epi wafers supply chain. The main objective of the project, started in March 2010, is to sustain the industrial development of semi-insulating silicon carbide substrates (SI SiC) and prove the industrial capability of Europe...
This paper reports on the evolution of electromechanical properties of dielectric-less RF MEMS switches under long-term stress conditions. Two different designs, one based on a clamped-clamped air bridge and the other on a cantilever beam, are characterized and compared by monitoring pull-in and pull-out voltages after a long-time application of different bias voltages. Results show that the beam...
The paper presents a low-cost technique for nonlinear characterization of active devices oriented to microwave power amplifier design. The approach is based on a recently proposed measurement technique which, by exploiting a direct low-frequency nonlinear electron device characterization in conjunction with a model-based description of the device strictly dynamic nonlinearities, achieves a similar...
This contribution presents an innovative solution to drastically increase the output power range in which the Doherty Power Amplifier shows a high and flat efficiency behaviour. The proposed topology and its main theoretical guidelines are shown and discussed. Moreover, the potentialities of the new idea and how it can solve some drawbacks in applications that manage signals with a peak to average...
A Current Mode Class D (CMCD) power amplifier at 900 MHz is presented. After a theoretical analysis, a class D amplifier is designed, simulated and afterwards assembled and characterized. Thereby, a maximum drain efficiency of 80.6%, and a maximum power added efficiency (PAE) of 72.8% at a switching frequency of 864 MHz, and an output power of 28.2 dBm were obtained. A linear class A amplifier using...
An empirical large-signal model for high power AlGaN/GaN metal-insulator-semiconductor HEMT (GaN MISHEMT) utilizing improved drain current (Ids) and gate charge (Qg) formulation is presented. The proposed modeling equations accurately model the asymmetric bell-shaped transconductance (Gm) characteristics and the peaking behaviors of gate capacitance (C11) over a wide bias range of operation. All the...
In this paper, an S-band internally harmonic matched GaN FET is presented, which is designed so that up to third harmonic impedance is tuned to high efficiency condition. Harmonic load pull measurements were done for a small transistor cell at first. It was found that power added efficiency (PAE) of 78% together with 6W output power can be obtained by tuning impedances up to 3rd harmonic for both...
Cost effective E-band transmitter and receiver chipset MMIC's, that use a three-dimensional MMIC technology optimized for flip-chip implementation, are under development. Here, the first edition of MMIC's successfully designed and fabricated are presented. The MMIC structure incorporates inverse TFMS lines so that a ground metal can be applied to cover the whole chip surface except for interconnect...
This paper reports on a 50W high efficiency wide band InGaP/GaAs high voltage HBT (HVHBT) two stage MMIC operating at 750MHz to 960MHz. It uses a high breakdown voltage, high ruggedness HBT process developed by TriQuint Semiconductor. The device employs a temperature compensation bias circuit to stabilize bias current change over temperature. The P-1dB of the device reaches 47dBm (50W), with a gain...
We present a method to realize a low-power and highspeed Digital-to-Analog converter (DAC) for system-on-chip applications. The new method is specially suited for modern BiCMOS technologies. A prototype 5 GS/s DAC is implemented in 0.13μm SiGe BiCMOS technology. The DAC dissipates 26 mW and provides an SFDR higher than 48 dB for output frequencies up to 1 GHz.
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