Electromagnetic Waves Radiation by a Vibrators System With Variable Surface Impedance

Abstract

Abstract-The problem of electromagnetic waves radiation by a vibrators system with variable distributed surface impedance along their axes located in free space is solved by the generalized method of induced electromotive forces (EMF). The distinctive peculiarity of this method is the use of the functional distributions, obtained as a result of the analytical solution of the integral equation for the current by the asymptotic averaging method before, as the basic approximations for the currents along the impedance vibrators. The multi-parameter characteristics of three-element and multi-element antennas with variable impedance vibrators are calculated.

Formation of Radiation Fields of Linear Vibrator Arrays by Using Impedance Synthesis

“…Then, taking into account Eq. (20), we can write the expression for the resulting field in the free space as [7,10]…”

“…According to Formula (22), the maximum of the array RP is reached in direction (θ = π 2 ; φ = π 2 ) when u = 0. On the other hand, it is known [7,10] that if the phase shift between neighboring vibrators is equal to −∆u, the maximum of the array RP is shifted in the direction (θ max ; φ max ) determined from the relation sin θ max cosφ max = ∆u/kd [3,6]. In this case, we can write…”

“…In this article, a new approach to scanning of the RP of a linear vibrator arrays is presented based on impedance synthesis of radiators. This conception has been aroused from the analysis of impedance vibrator arrays [7,8], and it can be considered as an improved method for synthesis of antenna arrays with reactive loads [9,10].…”

Impedance Synthesis of Plane Diffraction Vibrator Arrays

“…If the difference of geometric path for the waves propagating from neighboring vibrators and observation point C (r, θ, ϕ) is taken into account, the expression for the total secondary radiation field in the wave zone can be presented based on Eq. (4b) as follows [4,7,8]…”

“…Of course, the diffraction arrays with discrete-switching can be implemented by using different types of elements, including impedance vibrators. In this case, there exists a possibility to use a surface impedance of vibrator elements as additional factor to control the array RP by varying electrical lengths of the vibrators and, therefore, the amplitude-phase distribution over the array aperture [4,5]. From these positions, the authors studied the one-dimensional antenna dipole array in [6], where the application of impedance synthesis for controlling scanning angles of the array RP maximum was justified.…”