Specialization: 011200 Physics
Profile: 01 Wave processes and methods of their investigation
Profile manager: head of department, prof. N.N. Zernov 
Department of Radiophysics  
Supervisor: Senior Researcher O.I. Stolyarov
Referee: Assoc. Prof. M.A. Pavlejno

Radio-wave sensors of measuring systems based on the helical resonator
D.I. Naumov

In the work investigated the helical resonator as radio-wave sensing element sensors of soil moisture (1), air humidity (2), permittivity of fuel and the air fraction in it (3). For evaluation of the sensitivity of sensors analytical calculation of dispersion equation for a helical waveguide in three-layers medium are executed. This waveguide exemplifies a physical model for a variety of sensors. A similar calculation in the literature executed approximately. On the basis of the obtained equation the numerical calculations for a resonance frequency finding of a helical resonator are executed. It allowed estimating sensitivity to changes in permittivity and geometrical parameters of one of the layers, which for selected version is a working layer. To evaluate the influence the air fraction in fuel performed an experiment to determine the sensitivity of the resonator to a small volume of air. Using techniques based on the perturbation method it was possible to simplify the experiment and to evaluate minimum air volume in fuel, which can detect modern digital apparatus.

The list of the publications
1.	Столяров О.И., Новиков А.Ю., Латышев Е.Е., Наумов Д.И. Исследование спирального резонатора как чувствительного элемента радиоволнового датчика. Региональная XIX конференция по распространению радиоволн. Сборник трудов конференции, Санкт-Петербург, 2013, с.123-126.
2.	 Наумов Д.И. Спиральный резонатор как чувствительный элемент радиоволнового датчика влажности воздуха, XVIII Всероссийская научная конференция студентов-радиофизиков. Тезисы докладов, Санкт-Петербург, 2015, стр. 73-74.