Low Intensity Microwave Fields and Radiation and Their Interaction with the Human Body

Sources of low-intensity microwave signals formation, which affect the metabolism processes when they interact with human body, are considered in the article. It’s noticed that increasing intensity level of the technogenic signals in environment significantly exceeds natural electromagnetic fields and radiation (EMR). The peculiarities of the registration and measurement of low-intensity signals parameters of the microwave range are considered. The processes of the interaction of the microwave signals and human organism are analyzed. Formation mechanisms of the positive and negative microwave flows of the electromagnetic radiation are revealed. Particularly, possible formation mechanism of the microwave EMR fluxes of implants in the human body. The results of the experimental study of the EMR signals levels of the objects contacting with human body, partly materials for bone defects replacement and soft tissues regeneration so as materials for physiotherapy, are given. The use of the term “electromagnetic compatibility” for materials which contacting the human body, is proposed. The expediency of its use is proven. Microwave properties of materials for clothes, minerals and building materials, which can affect the human body and environment, have been also studied.

Measurement of microwave radiation pressure on thin metal fibers

The pressure of electromagnetic radiation in the optical range is widely used to hold microparticles in a given place and control their movement. This is possible by focusing the laser radiation into an area with the dimension of several micrometers. The intensity of radiation in this area is large and sufficient to retain micro-particles in the laser beam and manipulate them. Nowadays, intensive research is underway on the use of microwave and terahertz radiation and the possibility of applying radiation pressure in these ranges. But in the microwave range, the focal spot dimension is much larger than in the optical one. Therefore, control of the objects whose dimensions are comparable to those of the focal spot using the radiation pressure requires very high power. For the objects with small dimensions, a small amount of radiation energy falls on them, and the acting force decreases. However, it is known that thin conductive fibers interact very strongly with microwave radiation. This can be used to levitate short thin metal fibers (vibrators), hold them in predicted place and control their position in space. The paper describes the measurements of the pressure of microwave radiation with a wavelength of 8 mm on thin copper fibers. Torsional balance is used for this purpose. In the metal case on a suspension from a tungsten fiber with a diameter of 8 microns there is located the rocker arm with 50 mm length with receiving elements in the form of system of copper fibers with a diameter of 300 microns and 15 mm length. Microwave radiation was directed to one of the receiving elements using a horn. The calibration of torsion balance, the measurement process, and the evaluation of the resulting error are described. The measurements gave the value of the efficiency factor of the radiation pressure Qpr = 4.86. This agrees satisfactorily with the results of calculations Qpr = 5.39. The difference is 10%.

Assessing Hydrological Changes in Wetland Areas of the Arctic and Subarctic Based on Microwave Remote Sensing Data

Specific emissivity features of swamps and wetlands of Western Siberia were studied for changing seasonal conditions with the use of daily data of satellite microwave sounding. The research technique involved the analysis of brightness temperatures of the underlying surface at the test sites. Variations in seasonal dynamics of brightness temperatures were mainly caused by different rates of seasonal freezing of the upper waterlogged layer of the underlying surface and dielectric characteristics of water containing natural media (water body, soil, vegetation). We analyzed long-term trends in seasonal and annual dynamics of brightness temperatures of the underlying surface and estimated hydrological changes in the Arctic and Subarctic. The findings open up new possibilities for using satellite data in the microwave range for studying natural seasonal dynamic processes and predicting hazardous hydrological phenomena.

Development of technological scheme of microwave - units for grain drying

In the agriculture of Ukraine, a variety of drying installations are used, the design of which should ensure uniform heating and drying of grain, while at the same time allowing to control the temperature and humidity in the grain mass. The choice of an appropriate dryer can significantly improve the quality of dried grain, increase production profitability, increase production, reduce drying costs, and reduce energy costs. Currently, the most common drying method is convective, the disadvantages of existing convective grain dryers are low efficiency, low specific moisture removal, uneven drying, high costs of the drying agent, high energy consumption. The purpose of the study is to develop a drying plant designed for high throughput. The use of grain drying technology using microwave electromagnetic fields provides a number of significant advantages over conventional dryers that use only a thermal agent. Grain drying technology using microwave electromagnetic fields can be used in combined dryers. The technological scheme of the drying installation is developed, which is based on the principle of microwave heating, which allows to intensify the external and internal transfer during drying. In the developed scheme the drying process takes place in three working zones. In the first zone, heating is carried out by irradiation with an electromagnetic field in the microwave range of seeds to a certain temperature, the second - the aging of the seeds, where moisture is released in the inter-grain space. In the third zone, the layer is blown by air flow with the organization of fluidization. The main design and mode parameters using the software environment "Flowvision" are determined. Key words: grain, microwave oven, dryers, installation, electromagnetic field

Scattering spectra of dielectric ring: microwave experiments

In recent years, dielectric ring resonators (RRs) have become an essential part of integrated optical circuits. This determines the growing interest in the study of the fundamental electromagnetic properties of these objects, which is far from complete. In particular, in the literature it is difficult to find information about light scattering spectrum, which should demonstrate a strong resonance character when the probe wavelength is comparable to the geometric dimensions of the RR, taking into account its dielectric constant. In this work, we present the results of an experimental study of the electromagnetic properties of a dielectric RR in the microwave range of the spectrum. The results of numerical calculations of the scattering spectrum are also presented, which demonstrate excellent agreement with the experimental data. In addition to the expected resonance character of the spectrum, we report the effects of strong light confinement, which are associated with Fano resonances between the eigenmodes and the component of the electromagnetic field scattered by the ring.

The key role of GNSS for monitoring geodetic parameters of the Earth

Глобальные навигационные спутниковые системы (ГНСС) являются основным инструментом для контроля геодезических параметров Земли, построения и постоянного контроля земной системы отсчета и связи измерений различных спутниковых геодезических технологий. ГНСС состоят из наземного сегмента (приемники ГНСС) и орбитальной группировки (навигационные спутники системы). Микроволновый диапазон сигналов ГНСС позволяет использовать данные системы при любых погодных условиях, а двухчастотные несущие позволяют, в значительной степени, исключить ионосферную задержку распространения сигналов. Помимо выполнения основных геодезических определений навигационные системы также могут быть использованы для решения социальных и других позиционных измерений, требующих высокой точности. В данной статье автором рассмотрены основные задачи, решаемые ГНСС, определены требования к точности продуктов навигационных систем и приведены направления развития наземной и орбитальных частей ГНСС, учитывая потребности мирового геодезического сообщества. Global navigation satellite systems (GNSS) are a fundamental tool for monitoring geodesic parameters of the Earth, building and constantly monitoring the Earth’s reference system and connecting measurements of various satellite geodetic technologies. GNSS consist of a ground segment (GNSS receivers) and an orbital grouping (navigation satellites of the system). The microwave range of GNSS signals allows using these systems in all weather conditions, and the two-frequency carriers allow, to a large extent, eliminating the ionospheric delay of signal propagation. In addition to performing basic geodetic definitions, GNSS can also be used to solve social and other positional measurements that require high accuracy. In this article the author discusses the main tasks solved by GNSS, defines the requirements for the accuracy of navigation systems products, and provides directions for the development of the ground and orbital parts of GNSS taking into account the needs of the international geodetic community.

Microwave technology: a novel approach to the transformation of natural metabolites

Microwave technology is used throughout the world to generate heat using energy from the microwave range of the electromagnetic spectrum. It is characterized by uniform energy transfer, low energy consumption, and rapid heating which preserves much of the nutritional value in food products. Microwave technology is widely used to process food such as drying, because food and medicinal plants are the same organisms. Microwave technology is also used to process and extract parts of plants for medicinal purposes; however, the special principle of microwave radiation provide energy to reaction for transforming chemical components, creating a variety of compounds through oxidation, hydrolysis, rearrangement, esterification, condensation and other reactions that transform original components into new ones. In this paper, the principles, influencing factors of microwave technology, and the transformation of natural metabolites using microwave technology are reviewed, with an aim to provide a theoretical basis for the further study of microwave technology in the processing of medicinal materials.

A Novel TDoA-Based Method for 3D Combined Localization Techniques Using an Ultra-Wideband Phase Wrapping-Impaired Switched Beam Antenna

This paper presents a novel Time Difference of Arrival-based approach suitable for single-anchor positioning systems, implemented by phase wrapping-impaired array antenna. With the latter being a typical occurrence in large Switched Beam Antenna (SBA) operating in the low microwave range. The proposed method takes advantage from the large bandwidth of radio link, established between the anchor and the positioning target, by generating an unambiguous equivalent phase relationship between antenna array elements. The technique is validated by adopting a relatively large SBA antenna operating in the 4.75–6.25 GHz bandwidth, and capable to position a target in a 3D domain. Experimental data, carried out in the 4–7 GHz frequency bandwidth, show that by dealing properly with the inherent constraint of phase wrapping issues, it is possible to get a significant improvement on the elevation angle with respect to methods not capable to deal with phase reconstruction and thus operating in a phase-less context. Combining range and angle errors, the associated cumulative distribution function error in 90% of cases shows an error of 0.13 m.