Reliability prediction of resonant tunneling diodes and non-linear radio signal converters based on them under influence of temperature factor and ionizing radiations

The methodology of predicting reliability of resonant tunneling diodes (RTD) and non-linear radio signal converters based on them is developed. Reliability of non-linear converters of radio signals is considered on the example of radio frequency identification (RFID) systems with passive tags, the reliability of which is estimated in terms of a parametric failure associated with the I-V characteristics drift of RTDs that are part of the tag rectifier under the influence of external factors beyond the tolerance limits. The methodology of the time to failure of the RFID passive tag power supply system calculation by the criterion of the minimum permissible range is presented. The developed methodology can be used in the design of RFID systems with passive UHF and SHF tags and other non-linear radio signal converters to predict their reliability under specified operating conditions. © 2020, Univelt Inc. All rights reserved

Spacecraft guidance, navigation and control based on application of resonant tunneling diodes in nonlinear radio signal converters

The prospects of application of resonant tunneling diodes (RTD) based on nanoscale AlAs/GaAs heterostructures in non-linear radio signal converters of spacecraft guidance, navigation and control systems are demonstrated. A diagnostic model of the RTD has been developed. It makes it possible to obtain the kinetics of RTD current-voltage characteristics and the indices of non-linear converters of SHF radio signals under the influence of destabilizing factors during operation. The experimental data of the RTD current-voltage characteristic kinetics under the influence of destabilizing factors are presented. © 2017 Univelt Inc. All rights reserved

Spacecraft guidance, navigation and control based on application of resonant tunneling diodes in nonlinear radio signal converters

The prospects of application of resonant tunneling diodes (RTD) based on nanoscale AlAs/GaAs heterostructures in non-linear radio signal converters of spacecraft guidance, navigation and control systems are demonstrated. A diagnostic model of the RTD has been developed. It makes it possible to obtain the kinetics of RTD current-voltage characteristics and the indices of non-linear converters of SHF radio signals under the influence of destabilizing factors during operation. The experimental data of the RTD current-voltage characteristic kinetics under the influence of destabilizing factors are presented. © 2017 Univelt Inc. All rights reserved

Simulation of transparent electromagnetic interference shielding materials based on periodic conductive networks

This paper is a preliminary report on a theoretical study of transparent shielding materials with potentially very high shielding efficiency based on quasi-periodic conductive networks. An empirical model for rapid calculation of shielding efficiency vs frequency and mesh geometrical parameters is suggested based on numerical simulation results. © Published under licence by IOP Publishing Ltd

Relationship between hardness and optical properties of diamond-like carbon coatings

Correlation between hardness and optical properties of diamond-like carbon (DLC) coatings is considered. Various methods for the characterization of mechanical, chemical and optical properties of DLC coatings are used; however, some of these methods are destructive, and others are non-destructive. It was found that optical properties of DLC coatings are proportional to their hardness. The mathematical expression that allows to calculate the hardness of a DLC coating according to its refractive index is proposed. Therefore, it is possible to avoid the use of destructive methods (such as nano-indentation technique) to characterize DLC coatings. © Published under licence by IOP Publishing Ltd

Resistance investigation of diamond-like carbon coatings to cyclic temperature changes

Optical elements used in outer space must be designed considering the effects of such factors as space vacuum, atomic oxygen in low Earth orbit, solar and space radiation, large temperature drops, gas release of spacecraft materials and structural elements, space dust and debris. In order to harden and protect mirror surfaces of optical elements from external factors, it has been promisingly applied diamond-like carbon coatings on their surface. These coatings are characterized by high strength and wear-resistant properties, in particular, high hardness, low friction coefficient, high wear resistance and chemical inertness. This leads to their widespread use in various fields of science and technology, including optical instrumentation. This paper presents the results of testing an aluminum mirror with a diamond-like carbon coating under the effect of cyclic temperature changes for determining their ability to withstand a rapid cyclic ambient temperature change, and specifically, to maintain optical and mechanical properties. © 2021 Institute of Physics Publishing. All rights reserved