Mammadov N. Wide-band antenna system for mobile objects of SW radiocommunication

The PhD thesis is devoted to research and development of wide-band antenna system for SW radiocommunication between mobile objects, including the identification of patterns and features of the radiation field formation, fre-quency changes of the input impedance of small-sized loop radiator with two-point excitation. A new technical solu-tion in the form of antenna system with improved characteristics was obtained on the basis of the research. New mathematical models of the input impedance, wave impedance of elliptical loop radiator with two-point excita-tion as well as radiation field of such antenna were developed. The algorithm for calculation of the characteristics of the loop radiator with two-point excitation was developed on the basis of the generalized method of induced electro-motive force (EMF). The potential wide-band and directional properties of the loop radiator with two-point excitation were revealed as well as their change in dependence on the geometric parameters of the loop radiator of the elliptic shape and amplitude and phase relationships of the exciting EMF; the presence of a radiation with a cardioid-like pat-tern. The principle of cardioid-like pattern formation is formulated for the loop radiator with two-point excitation. A new mathematical model of the excitation device in the form of wide-band phase shifter using the phase contours of the second order for the two-input loop antenna is developed and the method of phase contours parameters calcula-tion is developed as well; calculation, analysis and optimization of characteristics are performed. Applied software is created in MathCAD package for calculations, automated analysis and simulation of characteristics of loop antennas and antenna systems based on them.