Zoya E. Eremenko

Exact-calculated resonator method for permittivity measurement of high loss liquids at millimetre wavelength

We propose a new method to measure the complex permittivity (CP) of a high loss liquid at millimetre wavelength. The method is based on the use of an exact-calculated quasi-optical layered ball dielectric resonator. A monitored liquid is placed outside of the ball and does not disturb the spherical symmetry of the resonator. A dielectric layer between the ball and a liquid is used to dose the losses in the resonator induced by the measured high loss liquid. We obtained and numerically analysed the characteristic equations for resonant eigenfrequencies and also built the electromagnetic field distribution in the resonator. The resonant frequencies and Q-factor of the resonator are studied for various resonator and monitored liquid parameters. We found theoretically, and then confirmed experimentally, the optimal resonator parameters and an operating frequency mode to provide maximum sensitivity during CP measurement of a liquid. The CP measurement of a water–alcohol solution was carried out using the proposed method. Quite good agreement between our results and the results from other sources was obtained. The package of original computer software applications was designed to automate the experiment and calculate the CP values of high loss liquids using experimental data for the resonant frequency and Q-factor.

Improved differential Ka band dielectrometer based on the wave propagation in a quartz cylinder surrounded by high loss liquid under test

The differential dielectrometer was designed to measure small differences in complex permittivity (CP) of two high loss liquids at frequency 32.82 GHz. The measurements are fully computer-aided with the exception of liquids filling and draining in the measurement cells. The time of one measurement cycle does not exceed 3 min. The dielectrometer is easy-to-work and can be used under the conditions of scientific and industrial physical–chemical laboratories. The sensitivity of the difference in the phase coefficients of the electromagnetic waves propagated in the measurement cells is better than 0.05% and that of the attenuation coefficient is of the order of 0.2%. The dielectrometer contains two measurement cells that are dielectric quartz cylinders surrounded by high loss liquids. We developed the CP calculation algorithm using the known CP of the reference liquid and the difference coefficients of complex wave propagation in the cells. The origins of the measurement errors are studied in detail and recommendations were made to avoid some of them. The dielectrometer can be used to express the identification of wine and must authenticity by means of their CP values. The CP measurement results for solutions of some substances that make wine and must composition are obtained. The possibility of using the dielectrometer for the detection of added water in wines or musts is shown.

A millimeter wave dielectrometer for high loss liquids based on the Zenneck wave

The propagation of an electromagnetic wave in a dielectric rod placed in a high loss liquid was studied theoretically and experimentally. It is shown that the wave has a bulk character in the rod and a surface character in the liquid. The attenuation and phase velocity of this wave have strong dependence upon the dielectric properties of the liquid and the rod, while the phase velocity of this wave exceeds the light velocity in the rod material. It enables one to consider the studied wave to be similar to the Zenneck wave. A characteristic equation for the structure under study was derived and analyzed. The attenuation and phase velocity of this wave in the presence of distilled water and a water–ethanol solution were measured. Owing to these data, the real and imaginary parts of the complex permittivity of high loss liquids under test were determined. We have good agreement between the theoretical and experimental results. A differential dielectrometer based on the usage of the Zenneck wave was designed. Thus, the complex permittivity of high loss liquids with sufficiently high accuracy can be obtained. It is also possible to record a rather small difference between two similar liquids according to their dielectric properties.

Circular Layered Waveguide Use for Wideband Complex Permittivity Measurement of Lossy Liquids

The electromagnetic characteristics of a circular metal waveguide with a coaxial cylindrical dielectric insert and a layer of absorbing liquid that fills the space between the insert and the waveguide wall have been studied. The transverse waveguide dimensions are comparable with the wavelength. Dependences of the attenuation and phase coefficients of waveguide modes on the structure size and material properties of the layers are found by solving the boundary value problem. It is shown that based on the proposed layered waveguide with the HE11 type of wave, a measuring cell can be designed to work at either fixed frequency with high differential sensitivity or in the frequency range of the single-mode waveguide operation. The cell is of class of cells with calculable geometry. In this case, a reference liquid with known dielectric properties is not required for absolute measurements of the complex permittivity (CP) of the absorbing liquid. The method of finding the CP of absorbing liquids are verified using electromagnetic modeling with CST Microwave Studio.

Open-ended voltage multipliers for wireless transmission of electric power

ABSTRACT This paper presents a class of open-ended voltage multipliers, of which the input is a displacement current from a Goubau line and the output is a multiplied DC voltage. When terminated with a 500 ohm load, the proposed voltage multipliers have rectified a microwave power at 20 dBm into a DC voltage 5–6 V, corresponding to a conversion efficiency of approximately 50%. The maximum voltage reaches 20 V if the circuit is unloaded. Due to its characteristic impedance being comparable to that of the free space, the Goubau line feeding the proposed voltage multipliers has been successfully used as a monopole antenna for capturing ground waves in an experimental system for wireless power transfer. Over a short range, with r ≪ 1.05 m, the open-ended voltage multipliers vertically mounted on the surface of a lossy dielectric material were at best able to generate a power proportional to 1/r0.4, where r is the distance between the receiver and the transmitter, suggesting that the received power is not a pure space wave.

A study of the E-field dependence of resonant modes of a layered semi-ball immersed in lossy liquid

The amplitude–frequency dependences of a dielectric layered semi-ball resonator placed in a high loss liquid were studied experimentally and theoretically. It was determined that at definite relations between real and imaginary parts of complex permittivity of high loss liquid the electromagnetic field extrusion effect was observed. The extrusion effect means that the region of strongest E-field becomes displaced when the surrounding liquid has high loss, and may end up inside the resonator. Such an effect takes place when the resonator is immersed into the liquid with real and imaginary parts of complex permittivity that are much greater than 1 and the imaginary part is higher than the real one. Liquids with various real and imaginary parts of complex permittivity were studied. The existence conditions for the electromagnetic field extrusion effect were found. The influence of this effect on the measurement of complex permittivity of a high loss liquid using a sapphire layered semi-ball resonator was observed.

Influence of high loss liquid on the bandwidth of a circular two-layer waveguide at microwaves

ABSTRACT The electromagnetic waves propagation in a circular two-layer metal waveguide with a central low-loss dielectric rod surrounded by high loss liquid is studied in the microwave range. The dependence of the complex wave propagation coefficient on frequency and liquid layer thickness is obtained. The presence of high loss liquid surrounding the dielectric rod allows expanding the range of operating wavelengths of the standard waveguide from the millimeter to centimeter range, because the wave attenuation coefficient remains relatively small. We find that owing to a high loss liquid, such a waveguide does not have fixed values of cut-off frequencies. An extra low value of the wave attenuation coefficient is found in the centimeter wavelength range at certain liquid layer thicknesses. The proposed structure can be applied as a measuring cell for the determination of the complex permittivity of high loss liquids in small volumes and in a wide range of wavelengths.

Determination method of water-glucose solution concentration at microwaves

We have presented the practical application of complex permittvity dielectromerty method to identify the glucose amount in water solution for modelling the determination of the glucose amount in human blood. We used disigned by us the waveguide-differential dielectrometer for the complex permittivity determination of high loss liquids such as water and water solutions. The complex permittivity of glucose water solution as a function of the glucose concentration was determined for the concentration from 0 to 100 mmol/L. It was shown that at the increase of glucose concentration in water solution their real and imaginary parts of the complex permittivity decrease monotonically.

Dielectrometry of pharmaceutical ingredient solutions at microwaves

The practical application of dielectrometry method to identify the pharmaceutical ingredients was held. The proposed waveguide-differential dielectrometer is used for the complex permittivity determination of high loss liquid such as water and water solutions in the millimeter wave range. This method allows a real-time determination of pharmaceutical ingredient content in water solution by measuring values of wave attenuation and phase coefficients difference in the differential measurement cavity. The complex permittivity of anatoxin, penicillin, gentamicin, lincomycin and glucose in fluid form as a function of the concentration was determined. The dielectric properties of various pH solutions have been determined as well. The sensitivity measurement have been detected of the water — glucose solution for its real and imaginary parts equal to 1.12 and 0.68 mmol/L, respectively.

The absence of fixed cut-off frequencies in a circular layered waveguide with lossy liquid

The wave propagation in a circular metal waveguide with a central cylindrical dielectric rod and coaxial layer of absorbing liquid have been studied at the frequency range 5-30 GHz. Owing to the absorbing liquid the operating frequencies range can be extended up to centimeter wavelength range. This fact takes place because of the two-layered waveguide with absorbing liquid does not have fixed cutoff frequencies for waveguide modes. It has been found abnormally low attenuation coefficients of electromagnetic waves HE11 in the centimeter wavelength range at certain frequencies and values of thickness of the absorbing liquid. The sensitivity of the method of complex permittivity determination of absorbing liquid using a thin liquid layer increases in comparison with a thick layer.