STUDY OF DIRECTED AND WAVE PARAMETERS OF SURFACE WAVE ANTENNAS

Abstract

The research object of the work is the process of radiation of electromagnetic waves by the antenna of surface waves. The research subject is the surface wave antenna's directional and wave parameters. The proposed surface wave antenna with a ribbed retarder structure has a classic geometric configuration and operates in the operating frequency band from 7.25 GHz to 7.75 GHz. Its dimensions are a width of 38 mm, a height of 136 mm, and a length of 455 mm. The antenna is excited by an E-sectional rectangular horn antenna. As a retarding structure, a flat ribbed structure was chosen, which is a periodically repeating groove 2 mm wide and 6 mm deep with ribs 2 mm thick and a repetition period of 4 mm. The surface impedance of the retarding structure is inductive in nature and has a value of j1.65 Ohm, j1.75 Ohm, and j1.87 Ohm, respectively, for the minimum, middle and maximum frequency of the operating range. The paper obtained the results of electrical calculations and mathematical modeling of the directional and wave parameters of the surface wave antenna in the operating frequency range. At a minimum wavelength of λ = 38.7 mm, which corresponds to a frequency of 7.75 GHz, the width of the amplitude pattern is 21.9°, the level of the side lobes is 0.33, the coefficient of directional action is 59.94, the input resistance is 53.96 Ohm, the reflection coefficient 0.038 and standing wave coefficient 1.07. At a maximum wavelength of λ = 41.4 mm, which corresponds to a frequency of 7.25 GHz, the width of the directional amplitude diagram is 25.8°, the level of the side lobes is 0.32, the directivity factor is 39.93, the input resistance is 47.49 Ohm, the factor reflection -0.027 and standing wave coefficient 1.05. The developed surface wave antenna realizes optimal return loss and standing wave coefficient values. The advantage of the proposed antenna is the simplicity of the design, the constancy of the input resistance at the level of 50 Ohms, and the high-quality matching in the operating frequency range.