The flicker noise of the ferrite circulator is a critical element in ultra-stable microwave oscillators, in which the signal reflected from the input of the reference cavity is exploited to stabilize the frequency. This paper explains why the circulator noise must be measured in isolation mode, proposes a measurement scheme, and provides experimental results. The observed flicker spans from -162 to -170 dB[rad2]/Hz at 1 Hz off the 9.2 GHz carrier, and at +19 dBm of input power. In the same conditions, the instrument limit is below -180 dB[rad2]/Hz. Experiments also give information on the mechanical stability of the microwave assembly, which is in the range of 10(-11) m. The measurement method can be used as the phase detector of a corrected oscillator; and, in the field of solid-state physics, it can be used for the measurement of random fluctuations in magnetic materials.
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http://dx.doi.org/10.1109/tuffc.2004.1324399 | DOI Listing |
Microsyst Nanoeng
December 2024
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, 710049, Xi'an, China.
A differential microelectromechanical system (MEMS) quartz resonant accelerometer with a novel oscillating readout circuit is proposed. The phase noise in a piezoelectric quartz resonant accelerometer has been systematically investigated. A high-performance front-end is used to extract the motional charge from a piezoelectric quartz resonator for the first time.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India.
Creating van der Waals (vdW) homojunction devices requires materials with narrow bandgaps and high carrier mobilities for bipolar transport, which are crucial for constructing fundamental building blocks like diodes and transistors in a 2D architecture. Following the recent discovery of elemental 2D tellurium, here, we systematically investigate the electrical transport and flicker noise of hydrothermally grown multilayer tellurium field effect transistors. While the devices exhibit a dominant p-type behavior with high hole mobilities up to ∼242 cm V s at room temperature and almost linear current-voltage characteristics down to 77 K, ambipolar behavior was observed in some cases.
View Article and Find Full Text PDFJ Vis
December 2024
Psychology Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, UAE.
Angew Chem Int Ed Engl
December 2024
Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark.
One key aspect for the development of functional molecular electronic devices is the ability to precisely tune and reversibly switch the conductance of individual molecules in electrode-molecule-electrode junctions in response to external stimuli. In this work, we present a new approach to access molecular switches by deliberately controlling the flexibility in the molecular backbone. We here describe two new conductance switches based on bis(triarylamines) that rely on the reversible toggling between two conformers, each associated with vastly different conductances.
View Article and Find Full Text PDFSci Technol Adv Mater
October 2024
Institute for Regenerative Medicine, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russian Federation.
In live organisms, cells are embedded in tissue-specific extracellular matrix (ECM), which provides chemical and mechanical signals important for cell differentiation, migration, and overall functionality. Careful reproduction of ECM properties in artificial cell scaffolds is necessary to get physiologically relevant results of in vitro studies and produce robust materials for cell and tissue engineering. Nanoarchitectonics is a contemporary way to building complex materials from nano-scale objects of artificial and biological origin.
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