A. V. Abramov

Measurements of thickness of metal films in sandwich structures by the microwave reflection spectrum

The method for measurements of the thickness of nanometer metal films in sandwich structures by the microwave reflection spectrum had been proposed and implemented experimentally

Microstrip photonic crystals used for measuring parameters of liquids

Computer simulation and experimental study of the frequency dependences of the transmission and reflection coefficients of photonic crystals based on a microstrip structure are carried out in the case when the periodicity of the structure is violated by a change in the permittivity of the substrate of one of the alternating segments of the microstrip line. A method is developed for measuring parameters of the material playing the role of inhomogeneity in the open microwave photonic structure. The complex permittivity is determined for a number of polar and nonpolar liquids.

Variation of the type of resonance reflection of electromagnetic radiation from metal nanolayer-dielectric layer structures

Two types of resonance reflection of electromagnetic radiation from metal nanolayer-dielectric layer structures have been theoretically predicted and observed in experiment. These structures can obey the conditions of a half-wave resonance at a small metal layer thickness, and a quarter-wave resonance at a greater metal layer thickness.

Optical control of semiconductor synchronized microwave oscillators in the signals subtraction scheme

The influence of optical radiation on the performance of the synchronized microwave oscillator in the scheme of the coherent signals (synchrosignal and oscillator output signal) subtraction on the common load has been described theoretically and investigated experimentally. The high sensitivity of the characteristics of investigated scheme on the base of synchronized Gunn-diode oscillator has been shown.

Optical control of semiconductor synchronized microwave oscillators in the power suppression mode

The influence of optical radiation on the performance of a synchronized microwave Gunn-diode oscillator in the coherent signals subtraction mode has been described theoretically and investigated experimentally. The high sensitivity of the oscillator characteristics to the change of the optical intensity affecting the semiconductor diode structure has been shown. It is suggested to use this mode for the creation of optoelectronic microwave systems with the controlled amplitude and phase of the output signal and for the high-accuracy indication of optical radiation.

Microstrip Photonic Crystals and their Application for Measurement Parameters of Materials

The computer simulation and experimental investigation of frequency dependencies of the reflectance and the transmittance of photonic crystals based on the microstrip structures in the frequency band 0-20 GHz have been performed. The investigations were performed for the photonic crystal with irregularity introduced as changed geometry size of the stripline conductor or changed substrate permittivity of one of the sequence microstrip sections. Good quantitative fit between the calculations and experimental results have been obtained. The possibility of application of open microwave transmission lines - microstrip photonic crystals - for measurement parameters of a material which acts as irregularity in the photonic crystal has been demonstrated.

Waveguide photonic crystals with characteristics controlled with p-i-n diodes

A one-dimensional waveguide photonic structure—specifically, a photonic crystal with a controllable frequency characteristic—is designed. The central frequency of the spectral window of the photonic crystal can be tuned by choosing the parameters of disturbance of periodicity in the photonic crystal, whereas the transmission coefficient at a particular frequency can be controlled by varying the voltage at a p-i-n diode. It is shown that the possibility exists of using the waveguide photonic crystal to design a microwave device operating in the 3-cm-wavelength region, with a transmission band of 70 MHz at a level 3 dB and the transmission coefficient controllable in the range from −1.5 to −25 dB under variations in the forward voltage bias at the p-i-n diode from zero to 700 mV.

Wideband waveguide loading impedance matching on the basis of photonic crystals with nanometer metal layers

Theoretically shown and experimentally proven is the possibility of creating wideband matched loading on the basis of photonic crystals, composed of alternating nanometer metal and isolator layers with different electro-physical parameters.

Wideband Waveguide Matched Loads Based on Photonic Crystals with Nanometer Metal Layers

The possibility of creation of wideband matched loads based on waveguide photonic crystals consisted of alternating layers of dielectrics with different values of thickness and permittivity and nanometer-thin metals with different values of thickness and conductivity has been shown theoretically and proven experimentally.

Radiowave interferometry of human thorax displacement, related with breath and heartbeats

In this paper, the application of fixed-frequency and multifrequency radiowave interferometry using magic tee and Gunn-diode autodyne for detection of human respiratory shifts and heartbeats is presented. The methods, which provide remote detection of thorax shifts, caused by respiratory movements and heartbeats, are implemented; amplitudes and frequencies of respiratory movements and heartbeats are measured