Search results for "Low-noise"
showing 10 items of 13 documents
Design and implementation of a long-range low-power wake-up radio for IoT devices
2019
In this paper, we present the design and implementation of an on-demand wake-up radio (WuR) for long-range wireless IoT devices to reduce the power consumption, thereby increasing the life time of the devices. A custom narrow-band (NB) low noise amplifier is designed and implemented for WuR. The low-noise amplifier achieves a gain of 31 dB at 1 mA current consumption from a 6 V power supply. The WuR achieves a sensivity of -80 dBm by consuming just 1 mA, thereby optimizing the energy consumption of battery powered long-range IoT devices, hence reducing the power consumption and overall costs when deployed in large scale.
Proposal of Up-to-Date Standards on Methods of Measuring Noise Parameters of Microwave Transistors
1994
One of the most interesting topics for microrwave community is the characterization of low-noise transistors. After so many years, the Standards suggested by IEEE in 1960 are considered obsolete by the experimenters. A new methodology is here proposed as a standard. To support this proposal, an original measuring system for the complete characterization of microwave transistors in terms of noise, gain and scattering parameters from noise figure measurements only is presented.
Full characterization of low-noise HEMTs using only noise figure measurements
1993
A method for the complete characterization of microwave transistors in terms of noise, gain and scattering parameters using a computer-controlled noise figure measuring set-up only is presented. Selection of the optimum measuring conditions, all the steps of the experimental procedure, the data collecting and processing to derive all the parameters, are fully driven by an original (unpublished) software, even without the presence of an (unskilled) operator. Results are presented about the complete characterization of a series of ten pseudomorphicHEMTs in the 8-16 GHz range. The S-parameters are also compared with those measured by an ANA.
Modeling of low-noise microwave HEMTs for CAD-oriented applications
1993
The simultaneous determination of noise, gain and scattering parameters through a computer-driven noise figure measuring system allowed the rapid and accurate characterization of several samples of low noise HEMTs of the same family. From the measured parameters an equivalent circuit model representing the behavior of the typical device is extracted by means of a decomposition approach. Comparison between the model performance and the set of measured parameters of all devices are reported for the FHR 02FH (by Fujitsu). The modeling procedure is mainly oriented to the CAD of (M)MIC low noise wideband amplifiers. © 1993 John Wiley & Sons, Inc.
Modulating the polarization of broadband terahertz pulses from a spintronic emitter at rates up to 10 kHz
2021
Reliable modulation of terahertz electromagnetic waveforms is important for many applications. Here, we rapidly modulate the direction of the electric field of linearly polarized terahertz electromagnetic pulses with 1–30 THz bandwidth by applying time-dependent magnetic fields to a spintronic terahertz emitter. Polarity modulation of the terahertz field with more than 99% contrast at a rate of 10 kHz is achieved using a harmonic magnetic field. By adding a static magnetic field, we modulate the direction of the terahertz field between angles of, for instance, −53° and 53° at kilohertz rates. We believe our approach makes spintronic terahertz emitters a promising source for low-noise modula…
Microwave characterization and modeling of packaged HEMTs by a direct extraction procedure at cryogenic temperatures
2004
In the present work we employ a direct extraction procedure to determine small signal equivalent circuit of microwave GaAs FETs by means of scattering (S-) parameter measurements down to cryogenic temperatures. The direct extraction procedure was tested on packaged AlGaAs/InGaAs HEMTs and good agreement between the simulated and measured S-parameters was obtained at different bias and temperature conditions. We employed a properly designed cryogenic set-up operating in our laboratory that allows to perform DC and RF characterization down to 30 K.
Advanced PSA Bipolar Transistors for Wireless Applications: Measurements of Scattering Parameters and Noise Figure
1994
A complete investigation on the performance of a series of double polysilicon self-aligned (PSA) bipolar transistors in terms of scattering parameters and noise figure is here reported. The devices have been characterized over the 1-4 GHz frequency range in several bias conditions to the aim of assessing the optimum bias values for the best trade-off between noise and gain performance. This is the first part of an extensive investigation currently performed on 5 families of PSA devices having different emitter configuration and size which have been manufactured by SGS-Thomson to undergo a comparative analysis on the global transistor performance.
ACCURATE MEASUREMENTS OF OPTIMUM NOISE PARAMETERS OF MICROWAVE TRANSISTORS
1986
A method for measuring losses of the tuner network used as noise source admittance transformer in transistor noise parameter test-set is presented. Since the method is based on noise figure measurements, tuner losses can be determined on-line while performing measurements for determining transistor noise parameters. As experimental verifications the optimum noise parameters of a GaAs FET in the 4 - 12 GHz frequency range, measured through a computer-assisted measuring system, are reported.
Fast and efficient procedures for determining the microwave noise parameters of HEMT's at decreasing temperatures
1998
Noise parameters are an electrical representation of the noise performance of transistors which is widely used in reliability studies as well as in the design of low-noise microwave amplifiers. Such parameters are usually determined by employing a complex indirect (standard) procedure based on multiple noise figure measurements and appropriate data processing techniques. We report here two altemative and rapid methods used to perform the complete noise characterization of HEMT's at decreasing temperatures over the 6 to 18 GHz frequency range. The results show a very satisfactory agreement.among the different procedures thus assessing the inherent consistency of the global approach to the pr…
On the optimal design of multi-stage cascaded transistor amplifiers with noise, gain and mismatch constraints
2007
The problem of evaluating the optimal performances of cascaded, unbalanced, multi-stage transistor amplifiers is addressed. In particular, a theoretically rigorous approach is proposed for the determination of a family of Optimal Design Curves (ODC's) which express the best noise-gain tradeoff that can be achieved - at each frequency and device operating condition - when a simultaneous constraint on amplifier input VSWR is accounted for. Such curves can be used as a more meaningful starting point in practical amplifier design in place of the approximate calculations so far employed for target performance or optimization goals determination.