Coupling between transmission line antennas: analytic solution, FDTD, and measurements

Transmission line antennas are widely used elements. Analytical formulations for the coupling between transmission line antennas, e.g., loops and inverted-Ls, are developed. Furthermore, corrected current distributions that exhibit nonzero input current at the antiresonances of such elements are derived. The analytical results are compared with finite-difference time-domain (FDTD) calculations and measurements. Also, the physics of coupling is discussed. Finally, an FDTD technique that efficiently computes the two-port network parameters of a system of two antennas is developed based on a source with an internal resistance