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, a new quantity is
proposed to obtain spatial information about mutual coupling. The new
quantity is named the weak-coupling density. This quantity is a
real-valued scalar and can be visualized as a three-dimensional density
in space. It is also shown that there is a strong correlation between
regions with a positive (negative) weak-coupling density and decreasing
(increasing) the coupling when placing an absorber in that region. This
predictive ability is a useful feature, which is tested here for three
numerical cases. The results are robust to the shape of the platform,
and it persists over neighboring frequencies. By placing absorbers based
on the weak-coupling density, it is possible to reduce the required
amount of absorbers to obtain a certain mutual coupling reduction. The
visualization results and predictions of absorber positions are compared
with a Poynting vector based method. Placing absorbers based on the
weak-coupling density had a larger impact on the mutual coupling,
compared to the predictions with the Poynting vector based method in the
investigated cases.