Visualization and Reduction of Mutual Coupling Between Antennas
Installed on a Platform
Abstract
Mutual coupling, or equivalently, the isolation between antennas, is a
key parameter in antenna system design. In this work, the previously
defined impedance density is generalized, and it is demonstrated how it
can be used to obtain spatial information about the mutual coupling. The
generalized impedance density is a real-valued scalar and it can be
visualized as a three-dimensional density in space. It is shown that
there is a strong connection between regions with a positive (negative)
generalized impedance density and a decrease (increase) of the coupling
when an absorber is placed in that region. This predictive ability is a
useful feature, which is tested for three numerical cases. The results
are robust to the shape of the platform, and it can be compared across
frequencies. By placing absorbers based on the generalized impedance
density, it is possible to reduce the required amount of absorbers
needed to obtain a certain reduction in mutual coupling. The
visualization results and predictions of absorber positions are compared
with a Poynting vector based method. Placing absorbers based on the
generalized impedance density had a larger impact on the mutual
coupling, compared to the predictions with the Poynting vector based
method in the investigated cases.