Performance Analysis of Diffraction Gain (Gd) Due to Presence of single and Multiple Knife-Edge as Compared to Free Space E- Field and Identifying the Position of Obstacle in a Fresnel Zone | Chapter 07 | Novel Perspectives of Engineering Research Vol. 6

 This paper discusses diffraction, diffraction gain, diffraction loss, and field strength at the receiver as a result of single and multiple knife-edge obstacles in the signal's propagation path, i.e. between the transmitter and the receiver. The phenomenon of electromagnetic waves bending around obstacles is referred to as diffraction. This study also covers the entire concept of identifying the position of an obstacle in a Fresnel zone, diffraction loss, and the position of an obstacle with changing distances between source and field, as well as varying heights of obstacles in Fresnel zones, using tabular forms and charts. The Fresnel theorem is derived from a calculation based on an approximation of the contribution of each Fresnel zones to the total field: the total field is only one-half that due to the first zone alone.

The field due to each Fresnel zone can be determined precisely if the Fresnel zones are defined on a plane passing through the midpoint of the line connecting the source point and the field point. The contribution of the first zone is equal to the total field multiplied by the factor 1+ (l+ /nd')-2 when the Fresnel zones are established on a plane perpendicular to the line between the source and field locations. The wave number is n, and the distance between the source and field points is d'. As a result, the Fresnel theorem only applies for this geometry in the limit nd'1; for any nd', the factor stated must be applied.

Author(S) Details

P. Sankara Rao
Department of Electronics and Communication Engineering, St. Mary’s Group of Institutions, Hyderabad, India.

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