WAVE PROPAGATION IN A CIRCULAR BELOW CUTOFF TWO-LAYERED WAVEGUIDE WITH HIGH LOSS LIQUID AT FREQUENCY RANGE 5…30 GHz

Abstract

Methods for determination of complex permittivity of high loss liquids are essential in various fields of science and technology. The propagation of electromagnetic waves in a circular two-layer metal waveguide with a central low loss dielectric rod, surrounded by high loss liquid in the microwave range has been studied. The dependencies of the complex wave propagation constant on frequency and the magnitude of the liquid layer were obtained. The presence of high loss liquid surrounding the dielectric rod, allows expanding the range of operating wavelengths from the millimeter to centimeter range. The value of the decay constant is relatively small. Thanks to a high loss medium, this waveguide structure does not have a fixed value of the cutoff frequency. An anomalous low value of the attenuation constant of the electromagnetic wave has been detected at the centimeter wavelength range for certain operating frequencies and liquid layers. The proposed structure can be applied as a measuring cell for the determination of the complex permittivity of high loss liquids in small volumes.

Keywords

• attenuation coefficient
• centimeter wave range
• circular layered waveguide
• complex permittivity
• cutoff frequency
• high loss liquid
• millimeter wave