Factorization of Gaussian Coupling Efficiency and algorithm to compute it

Paper in proceeding, 2012

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, BOR 1, spill over, polarization and BOR 1 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 44 Microstrip patch Array is studied using this analysis and found that η G 70% is feasible for 320-350 GHz bandwidth.