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The creation of an electronic component base based on microelectromechanical systems is one of the main directions of the development of modern microelectronics and the basis for the construction of a new generation of radar and communication systems. This is due to the possibility of obtaining fundamentally new electrophysical properties of devices obtained on the basis of microsystem technology. Classification of devices based on microsystem technology includes: switches, varactors, resonators, actuators, filters, etc. Currently, the most widely used radio frequency MEMS switches. This is due, in particular, to the linearity of the transmission characteristics of radio frequency signal switches in a wide frequency range. Radio frequency devices built on the basis of microsystem technology have a good level of isolation (>30 dB) and low insertion losses (<0.5 dB). One of the factors that have a significant impact on the operation of the RF MEMS switch is the choice of materials. The design of the RF MEMS switch consists of the following main elements: substrate, conducting lines, dielectric, beam structures. The choice of materials for each of the listed elements is important, but the substrate material has the most significant effect on the operation of the RF MEMS switch. [ABSTRACT FROM AUTHOR]

Integration of electromagnetic (EM) wave absorber with patch antenna array on single substrate provides a very efficient way to improve the radiation pattern of array by reducing mutual coupling effect. The placing of absorber on array assembly may however affect the radiation characteristics due to the heat generated from absorbed power. As the microwave absorber dissipates the inter-element waves in terms of heat via absorption, the ambient temperature of array increases which consequently varies the patch dimensions and dielectric properties of the substrate thus shifting the resonant frequency of array. These effects have been investigated for graphene oxide-based absorber loaded rectangular patch array designed on different substrates such as silicon, gallium arsenide, aluminium oxide and Roger RO3210. On the basis of percentage variation in return loss and effective bandwidth an optimum substrate is proposed which undergoes minimize temperature effect without deteriorating the gain and directivity of the antenna array. The results show that for Graphene oxide-based absorber with Roger RO3210 substrate having high melting temperature of 4236.85 °C, side lobe level of array is reduced from 3.737 dB to 2.551 dB with increased major lobe gain. Due to absorbed power, ambient temperature of array increased from room temperature (27 °C) to 187 °C significantly shifting the resonant frequency from 10.4 GHz to 8.9 GHz. Further the comparison results show that with aluminium oxide substrate the array exhibits minimum temperature sensitivity hence proving to be a better choice for design of microwave absorber loaded antenna array. [ABSTRACT FROM AUTHOR]

Chemical mechanical polishing (CMP) has attracted much attention for high-performance manufacturing and setups, in which the surface roughness Ra is required to be less than 1 nm. In CMP, abrasives play a significant role in polishing quality and efficiency. Herein, we review the synthesis methods of abrasives including sSiO2@mSiO2, PS@CeO2, PS@SiO2 composites and their applications in CMP slurries. Then, the problems and solutions in CMP for soft- and hard-brittle solids and metals are presented in detail, such as cadmium zinc telluride (CdZnTe, soft brittle), silicon carbide (SiC, hard brittle) and copper (Cu, metal). After that, we summarize the molecular dynamics simulations of the CMP processes. Finally, the current problems of CMP and its development perspectives are discussed. [ABSTRACT FROM AUTHOR]