Generalized freespace equation for computation of power transferred between two antennas
Abstract
A freespace, radio frequency communications link over which antennas A sub t transmits and antenna A sub r receives is defined. The two antennas are stationary, but they may be oriented with respect to one another in any way. For this link, a generalized freespace equation is derived that one can use to exactly compute power transferred between A sub t and A sub r. The form of the generalized equation is very similar to that of the normal freespace equation; however, to account for polarization characteristics of the antennas, the product gain term (G sub t G sub r) is written as the squared magnitude of the dotproduct of two complex vectors, one for A sub t and one for A sub r. Each vector is a function of three measured antenna patterns; each vector completely described both radiating and receiving properties of the antenna to which it applies.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 September 1980
 Bibcode:
 1980STIN...8113256A
 Keywords:

 Antennas;
 Mathematical Models;
 Radio Transmission;
 Antenna Radiation Patterns;
 Matrices (Mathematics);
 Polarization Characteristics;
 Spherical Coordinates;
 Vectors (Mathematics);
 Communications and Radar