Factorization of Gaussian Coupling Efficiency and algorithm to compute it

Gaussian Coupling Efficiency (η_G) quantifies the amount of radiated power getting coupled to fundamental gaussian beam mode. This paper focus on the computations of η_G for antennas from their far-field data. The mathematical analysis presented in the paper shows that the term η_G can be factorized into sub-efficiencies namely, BOR₁, spill over, polarization and BOR₁ to Gaussian Coupling. This analysis is based on the definition of Body of Revolution type of antennas (BOR). Based on the analysis, an algorithm is developed to compute η_G of Antennas. This algorithm accepts the far-field data of antenna as input and computes the optimum values of Beam Waist (ω_o) and it´s location (z_o) for maximized η_G. The algorithm is verified using Smooth Conical Horn. The beam parameters (ω_o & z_o) of Conical Horn obtained from near field measurements agree well with the beam parameters obtained from the simulated far-field. The 4 × 4 Microstrip patch Array is studied using this analysis and found that η_G >; 70% is feasible for 320-350 GHz bandwidth.