Transient radiation from aperture antenna under non-synchronous excitation

A number of papers has been devoted to the thorough theoretical investigation of radiation characteristics of aperture antennas under synchronous transient excitation [1-3]. At the same time, a few works was directed to the problem of non-synchronous excitation of such antennas [4]. In this work, we describe a general problem of radiation from a rectangular aperture excited with transient signal of arbitrary time dependence and amplitude distribution of a current density over aperture taking into account arbitrary non-synchronous function of excitation

Van Attа’s array consist of tapered slot antennas for wideband pulse signals

The possibility of retrodirective radiation of a wideband pulse signal by Van Atta’s array is verified experimentally. The effect of both symmetric and asymmetric array elements interconnections is shown as regards the time form of the reradiated pulse

Effect of the low energy electromagnetic radiation of cell phone frequency (1.8 GHz, 2.4 GHz) on the chromatin state in cells of human buccal epithelium

The effect of low energy electromagnetic radiation with frequencies 1.8 GHz and 2.4 GHz on the heterochromatin granules quantity (HGQ) in the nuclei of human buccal epithelium cells was studied. Exfoliated cells were exposed to microwave radiation (frequency 1.8 GHz, surface power density 2.5 μW/cm2; and also frequency 2.4 GHZ, surface power density 2.3 μW/cm2). After exposure to microwaves during 1, 2, and 3 h, immediately or after delay of 1 or 2 h cells were stained with orcein (2% solution in 45% acetic acid). Cell exposure to microwaves induced condensation of chromatin. The biological and medical meanings of the data obtained are discussed

Radiation of short pulse signals from arrays of tapered slot antennas

The paper considers pulse radiation by 2D arrays and by two orthogonal 2D arrays made of tapered slot antennas. We show the possibility of 2D beam scanning by providing a special time delay for the excitation of the radiating elements, as well as control of polarization of the radiated signal together with the shape of the radiation pattern. The influence of array elements not being equidistant is studied

The radiation of wideband signals by tapered slot antennas with synthesized profile

The paper investigates the radiation characteristics of a tapered slot antenna (TSA) with a synthesized profile when the antenna is excited by monochromatic and wideband pulse signals. The profile is designed with the following requirements: wideband matching of the antenna with the feed line and with radiation space; optimization of the antenna's radiation characteristic. A decomposition method is used for calculating the radiation pattern. In this case, the antenna can be represented as the set of small apertures

Radioabsorbing and diffusing materials and theirs application

For radio engineering testing-grounds equipment, test/anechoic chambers, RF screened-out rooms, there have been developed, and made ready for manufacturing, a range of new materials and constructions which suppress wideband reflection in the band from 2 mm to 3 m. They can also be used for the technical personal protection against radio-frequency irradiation

Multibeam antenna for the matrix radiometric imaging systems

Ways of practical implementation of matrix radiometric systems (multibeam antennas and multichannel radiometric receivers), located onboard of various purpose aircrafts, intended for creation of images of ground-based objects have been substantiated. It is shown that formation of two-dimensional images for a short exposure time is possible both owing to application of the matrix radiometric information sensors, as well as on the basis of multi-channel radiometric sensors with the channels multiplexing according to the form of signals using the Walsh function

The process of recovery of cell membrane damage produced by the lowlevel microwave radiation

The process of cell membrane recovery after the influence of microwave radiation (f = 36.64 GHz, E = 10, 100, 400 μW/cm2, irradiation time 10 s) on human buccal epithelium cells was investigated. The stainability of cells with indigo carmine (5 mM) or trypan blue (0.5%) after 5 min of staining was investigated. It was shown irradiation to be induced decrease of percentage of unstained cells. Recovery of cell membrane permeability after microwave irradiation was shown. Cell recovery after microwave irradiation of low intensity (10 μW/cm2) was shown after 1 h. Microwave irradiation of higher intensity (100, 400 μW/cm2) induced more strongly effects of cell membrane permeability. Cell recovery after microwave irradiation of higher intensity was shown after 3 h. For the first time recovery of cell membrane after microwave irradiation of low intensity was shown

3D scanning by multilayered circular TSA array with pulse excitation

The characteristics of space-time domain form of the field, radiated by multilayered circular tapered slot antenna arrays were extended from [1, 2]. Peak power pattern was calculated for different polarities and time delay arrays element excitation. The possibility of spatial synthesis of radiation pattern through excitation polarities and time delay of arrays excitation was shown

Simulation of microwave exposure of human cells by electromagnetic field of EMF band

To implement a novel method of investigation of electromagnetic field action on state of cell nucleus the simulation of irradiation of the cells of human buccal epithelium by electromagnetic field of EMF band is carried out. The cells were exposed to radiation of frequency f = 36.64 GHz, with power densities W = 10–1, 1 and 4 W/m2during 10 seconds. To answer on the question of existence of nonthermal biological effect of electromagnetic field onto living cells the specific absorption rate (SAR) of a solution that contained cells is calculated. The numerical simulation based on FDTD method permitted to take into account different parts of experimental setup to obtain real distribution of electromagnetic field inside irradiated solution