An assessment of bio-radiolocation monitoring of respiratory rhythm during sleep is given. Full-night respiratory inductance plethysmography (RIP) and bio-radiolocation (BRL) records were collected simultaneously in a sleep laboratory. Polysomnography data from 5 subjects without sleep breathing disorders were used. A multi-frequency bioradar with step frequency modulation was applied. It has 8 operating frequencies ranging from 3.6 to 4.0 GHz. BRL data are recorded in two quadratures. Respiratory cycles were detected in time domain. Obtained data was used for the evaluation of correlation between BRL and RIP respiration rate estimates. Strong correlation between corresponding time series was revealed. BRL method is reliably implemented for estimation of respiratory rhythm and respiratory rate variability during full night sleep.
The paper contains feasibility study of a method for bioradar monitoring of small laboratory animals loco-motor activity improved by using a corner reflector. It presents results of mathematical simulation of bioradar signal reflection from the animal with the help of finite-difference time-domain method. It was proved both by theoretical and experimental results that a corner reflector usage during monitoring of small laboratory animals loco-motor activity improved the effectiveness of the method by reducing the dependency of the power flux density level from the distance between antennas block and the object.
This paper presents the results of experiments and mathematical simulation carried out to confirm the possibility of using holographic radar for the detection of breast tumors. In the work the software designed for the numerical solution of electromagnetic problems using the Finite-Difference Time-Domain Method. The simulation was performed with the three probe frequencies 4, 7 and 15 GHz. The model is a parallelepiped with dimensions 200×200×100 mm - mimicking the normal tissue of the breast, with the inclusion of a sphere - malignant neoplasm of breast tissue, the radius and depth of which have been varied. Frequency dispersion of normal and malignant tissues dielectric properties (conductivity and permittivity) was taken into account. It was shown both by theoretical and experimental results that it is preferable to use lower-frequency probing signal, namely, 4GHz, which can detect the inclusion of 5 mm diameter up to a depth of 10 mm. While using of probing signals of 7 and 15 GHz the depth limit of detection inclusion is not more than 5 mm, which is caused by the high attenuation in a medium. However, their usage is preferred because of higher resolution.
The paper summarizes results of step-frequency radars application in medicine. Remote and non-contact control of physiological parameters with modern bioradars provides a wide range of possibilities for non-contact remote monitoring of a human psycho-emotional state and physiological condition. The paper provides information about technical characteristics of bioradars designed at Bauman Moscow State Technical University and experiments using them. Results of verification experiment showed that bioradars of BioRASCAN type may be used for simultaneous remote measurements of breathing and heart rate parameters. In addition, bioradar assisted experiments for detecting of different sleep disorders are described. Their results proved that method of bioradiolocation allows correct estimation of obstructive sleep apnea severity compared to the polysomnography method, which satisfies standard medical recommendations.