CHARACTERISTICS OF VIBRATOR ARRAYS DIRECTIVITY ON HARMONICS OF MAIN FREQUENCY

Abstract

Antenna patterns representing dependences of the directivity factor (DF) on angular coordinates for arrays formed from Yagi-Uda aerials are considered and discussed. The results of computer modelling are based on the decision of integral equations by the method of moments. Patterns that represent dependences of the coefficient of the directivity factor (DF) for an array and her elements from angular coordinates are counted on fundamental frequency and four harmonics. The data obtained confirmed the validity of the assumptions that the directivity properties of vibrator antenna arrays can significantly affect the EMC conditions for harmonics of the fundamental frequency. At these frequencies, several main maxima appear in the radiation patterns, the level of directivity in which may even exceed the maximum directivity in the main lobe at the fundamental frequency. The DF patterns shown in the article refer to the case of in-phase excitation of the active elements of the array (without supply lines). However, in the presence of such lines with sequential or mixed power supply circuits, the dependence of the directivity on the angular coordinates can change significantly. The presence of bandpass filters in the input and output stages of the radar will make it possible to largely suppress the levels of harmonic interference, however, if these filters are made on the basis of transmission line segments, their parameters at harmonic frequencies may be insufficient. Further research can be aimed at studying the spatial characteristics and directivity of vibrator antenna arrays based on wave channel antennas with an increased number of passive vibrators, as well as with various power supply and filtering schemes.