Mutual coupling of two collocated orthogonal loops

While coupling between two parallel thin wire loops has been considered in the past, coupling between two orthogonal loops has not been discussed to our knowledge. With the increasing interest in compact complete polarization diversity antennas, it becomes important to understand coupling between closely located orthogonally oriented antenna elements. Coupling between two collocated orthogonal loops is analyzed. Two coupled integral equations for the loop currents are derived and their solution in general form is found in terms of a Fourier series. It is found that strong coupling can exist for first and higher loop current harmonics. It is also found that coupling for orthogonal collocated loop antennas depends on the relative locations of the antenna terminals on the loops.