The split-cylinder resonator method was adapted to measure the microwave properties (dielectric permittivity and loss tangent) of thin ferroelectric films on a dielectric substrate. The mathematical model for calculating the resonance frequency of the split-cylinder resonator was adjusted for the “ferroelectric film—substrate” structure. An approach for correcting the gap effect based on calibrating with a single-layer dielectric was introduced and used to study two-layer dielectrics. The prototype of a split-cylinder resonator designed to measure single-layer dielectric plates at a frequency of 10 GHz was presented. The resonator calibration was performed using dielectric PTFE samples and fused silica, and an example of the correction function was suggested. The measurement error was estimated, and recommendations on the acceptable parameter range for the material under investigation were provided. The method was demonstrated to measure the microwave properties of a ferroelectric film on a fused silica substrate.

A method for enhancing the adhesion properties of polytetrafluoroethylene (PTFE) surfaces is presented. The approach employs a fast neutrals flow generated by a DC glow discharge plasma with a grid neutralizer. Low power levels (≈6 W) provided by the stable DC discharge prevent physical sputtering and surface damage, while strong UV radiation from pure argon promotes efficient defluorination. The choice of working gas composition, discharge parameters, and treatment duration was informed by plasma emission spectroscopy, water contact angle (WCA) measurements, and systematic optimization. The combined effect of low-energy neutral particles and UV radiation leads to a significant increase in surface energy to 82 mN/m and a reduction in WCA to 13°, confirming the effectiveness of the proposed method. Thanks to its simplicity, scalability, and reliability, the method holds significant potential for industrial applications.

The advanced design of a millimeter-wave quasi-optical beamforming device (QOBD) based on the ferroelectric ceramic was elaborated and considered. Among the advantages of the proposed design are simplicity and cost-effectiveness in contrast to conventional analog and digital beamforming devices based on array antennas. The use of ferroelectric ceramic in the QOBD design allows operating in a wide frequency range up to 100 GHz. The advanced topology of discrete radiotransparent electrodes to provide a realization of different beamforming functions such as beam focusing and beam scanning was considered. The prototype of the proposed QOBD was designed to operate at 60 GHz. The measured radiation pattern of the QOBD prototype is in good agreement with the simulated one. Measurements demonstrate decreasing of beamwidth of the primary antenna radiation pattern by the lens prototype operating in the beam focusing regime.

Millimeter waves are increasingly used in modern telecommunication systems for wireless data transmission. However, higher path loss, especially caused by non-line-of-sight scenarios, remains challenging. The design of an electrically controllable reflector for the millimeter-wave range is elaborated and presented in this manuscript. The reflector design was based on distributed ferroelectric ceramic elements and could be used in a frequency range up to 100 GHz. The issue of the ferroelectric reflector impedance matching was analyzed in detail. Two possible implementations of the reflector for indoor and outdoor communication systems were considered and simulated. The prototype of the proposed reflector for an operating frequency of 60 GHz was manufactured. Both simulation and measurement results demonstrated the beam steering by the proposed ferroelectric reflector.