POSSIBILITIES OF INCREASING THE ENERGY OF RADIO LINES FOR CONTROLLING DRONES

Background. The creation of an antenna system consisting of two spiral structures for the 2,4 GHz and 5,8 GHz frequency bands is caused by practical needs determined by the results of using drones to monitor the environment. The proposed technical solution was based on a study of known antennas for the 2,4 GHz (right circular polarisation) and 5,8 GHz (left circular polarisation) frequency bands. Due to the mismatch of the polarisation of the electromagnetic wave and the antenna, losses of up to 20 dBp can occur. To reduce losses, a design of spiral antennas with the ability to change the polarisation direction was proposed. The article discusses the physical nature of the work and the relationship between the design and electrical parameters of spiral antennas. These provisions provide directions for improving these characteristics and technical solutions for their realisation. When creating the proposed design, the core issue was to solve the problem of matching the direction of polarisation of the electromagnetic wave generated by the antenna of the ground control station with the direction of the drone antenna rotation. The problem is proposed to be solved by ensuring the possibility of promptly changing the polarisation of the ground control station antenna. The prototype for the development of such an antenna is a well-known antenna without the possibility of changing the polarisation, which has two coaxial spirals for the frequency bands 2,4 GHz and 5,8 GHz with different types of polarisation. Objective. The article aims to develop a dual-band antenna system for a ground control station with the ability to change the direction of rotational polarisation. Methods. A certain number of sources concerning rotationally polarised antennas, various types of ultra-high frequency antennas, and their application for communication between a ground control station and a drone have been reviewed and analysed. According to the problem statement, spiral antennas were selected for the antenna array elements, which provide the possibility of communication with a drone when changing the direction of rotational polarisation. Various antenna designs can solve the creation of a rotationally polarised wave. One solution is to use horn antennas and vibrator-type antennas; however, from the perspective of the ratio of antenna gain and its dimensions, it makes sense to choose a spiral antenna. Results. The results of modelling the structural, technical, and electrical characteristics of the antenna system indicate the possibility of creating a dual-band spiral antenna design for use on ground control stations for radio contacts with UAVs in the frequency bands 2,35 ... 2,45 GHz and 5,75 ... 5,85 GHz. Conclusions. The implementation of the antenna system of spiral antennas for ground control stations in the frequency bands 2,35 ... 2,45 GHz and 5,75 ... 5,85 GHz for drone control makes it possible to change the direction of rotational polarisation, which is related to the drone antenna’s rotational polarisation direction.