In rapid deployments of next generation wireless communication system, the demand for high speed data, capacity, high reliability, low latency and increased flexibility. Rigorous research in the field of 5G technology. Sub-6 GHz mid-band spectrum fetches the attention of the researchers due to its estimable ease of deployment in the existing infrastructure. 5G Sub-6 GHz band finds massive applications in fields of wireless communication. The Sub-6 GHz wireless bands are assigned for various applications. This article gives inclusive review of current state-of-art of antenna for 5G Sub-6 GHz technology. Different design techniques and methods of antenna to Sub-6 GHz are summarized in the literature, to overcome the antenna design challenges.

A mathematical model of a passively Q-switched solid-state laser based on ytterbium and erbium codoped active media with transverse pumping by linear laser diode arrays has been developed. The gain in the laser is calculated using rate equations taking into account the space-time dependence of the pump radiation intensity in the laser element. The output laser characteristics, the pulse energy, the peak pulse power and the pulse duration, are calculated using analytical equations obtained for a passively Q-switched solid-state laser in the approximation of a "slow" saturable absorber. The model allows one to find the range of parameters of the active element, passive modulator, resonator, and pumping system at which the generation threshold is reached and the laser generates pulses with the required energy and duration. Modeling results were used for the experimental development of lasers with an active element based on phosphate glass doped by ytterbium and erbium ions. The energy and duration of the output light pulses were ≈ 1 mJ, ≈ 40 ns, and ≈ 2 mJ and ≈ 20 ns, depending on the content of ytterbium and erbium ions in the active element, as well as on the initial transmission of the passive modulator and the resonator parameters.

In electronic equipment it is often necessary to estimate the level of electrical signals of various shapes, the most adequate characteristic of which is the root-mean-square value of voltage V_RMS . It is preferable to use alternating current-to-direct current converters by the root-mean-square value (so called RMS-DC converter) based on thermoelectric converters to determine V_RMS for which electrical circuits have been developed and recommendations for selecting components to minimize the conversion error have been formulated. However a small value of the conversion error is not the only requirement for the RMS-DC converters in electronic equipment. It is usually necessary to search for a сompromise combination of a set of parameters. The aim of the work is to develop recommendations for the circuit and design synthesis of RMS-DC converters with different combinations of technical and economic parameters. The article presents results of the RMS-DC converter components main parameters assessing that determine the error, resistance to mechanical and radiation effects, and the cost in small-scale production. Comparison of components is carried out on the basis of experimental data, presented in the form of tables and graphs based on the results of measurements, use of which allows for synthesis of measuring voltage converters with various combinations of technical and economic parameters. Specific recommendations for selection of components for three types of measuring converters: inexpensive with an average level of parameters, precision, radiation-resistant are formulated.

The object of the study was aluminum substrates for creating sensor devices based on anodic aluminum oxide, which underwent mechanical processing in the form of grinding and straightening. The subject of the study was the detection of residual mechanical stresses and other surface defects to assess the quality of this processing using the scanning Kelvin probe technique. The technique applied allows for the effective detection of residual plastic deformations of aluminum substrates resulting from their mechanical processing with a resolution sufficient to detect mechanical stresses associated with individual roughnesses.

One of the key problems in the operation of fast neutron reactors cooled by a heavy liquid metal coolant is the formation and accumulation of various deposits. These deposits complicate the process of equipment restoring during repair work. This leads to a shorter work life and a lower efficiency of the equipment as a whole. Except of core destruction cases, the processes of formation and movement of impurities in a circuit with a heavy liquid metal coolant proceed rather slowly over time. So that time from request to receiving of complete information about the system status is an important aspect of its work. The purpose of the work was to control the composition, quantity and condition of impurities in all possible states (present as a solution in the heavy liquid metal coolant, passivated conglomerates on the inner surfaces of the contour, as well as on the free surface of the heavy liquid metal coolant). As well as the development of a set of devices that allows controlling of these processes. The paper considers the processes of mass transfer in the circuit, taking into account the influence of the resulting impurities affecting the state of the system. Sectoral control systems are proposed for use, which make it possible to quickly and reliably monitor impurities and their composition

Method of recording responses to radiation exposure is considered using the X-ray complex RIK-0401 and it is shown that for linear voltage regulators integrated circuits it allows diagnosing presence of changes in their topology. Four types of integrated circuits (ICs) of IS-LS1-1.8V type have been studied. They are equivalent in their main electrical parameters, but have differences in the output key design (vertical transistors with different base wiring), current mirrors and differential stages. ICs have modified design of the output key base: 1) vertical p-n-p-structures (Type 1); 2) mixed (lateral+vertical) p-n-p-structures (Type 2); 3) design as in the foreign analogue and vertical p-n-p-structures (Type 3); 4) design as in the foreign analogue and mixed (lateral+vertical) p-n-p-structures (Type 4). It has been found that the highest radiation hardness to the total ionizing dose effects is demonstrated by samples of Type 1 and Type 2. RADON-23 laser complex (with a maximum energy density of 200 mJ/cm²) has been used for examination of voltage regulator samples to impulse ionizing radiation hardness. The thyristor effect has not been fixed in all studied samples of Type 1–4. Results of the research allow developing methods for increasing the radiation hardness of the IS-LS1-1.8V by varying the topology of microcircuits and choosing the most advantageous option for manufacturing the output key.

A comparative analysis of the reflectance-absorption spectroscopy method’s application using the diffuse reflection factory prefix DRIFT of the ALPHA IR spectrophotometer and the method of attenuated total reflection for study of the optical characteristics of the FP9120, AZ nLOF 2020, 2070, 5510 and KMP E3502 photoresist films with a thickness of 0.99–6.0 μm formed on the plates of monocrystalline silicon by centrifugation has been carried out. In the reflective absorption IR spectra absorption bands are observed on the background of interference bands which makes it possible to determine the refractive index of a photoresist at a known geometric film thickness. It is shown that the reflective absorption spectroscopy method using the diffuse reflection factory prefix DRIFT has both a higher sensitivity compared with the attenuated total reflection method and is suitable for non-destructive interoperative control during semiconductor electronics devices’s manufacturing. The most intense in the reflective absorption spectra of AZ nLOF and KMP E3502 photoresistive films are bands of valence vibrations of the aromatic ring (≈ 1500 cm^-1), pulsation vibrations of the aromatic ring carbon skeleton (double maximum ≈ 1595 and 1610 cm^-1) and a band with a maximum of ≈ 1430 cm^-1 due to vibrations of the benzene ring, connected to the CH bridge. It was established that differences in the reflective absorption spectra of negative photoresist of different manufacturers – MicroChemicals (AZ nLOF series 2000) and Kempur Microelectronics (KMP E3502) are associated with various technologies of phenol-formaldehyde resin production and the residual solvent presence in the films.