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.

Visualization and Reduction of Mutual Coupling Between Antennas Installed on a Platform

“…V 22 and I 22 correspond to a nonideal current source connected to Port 2, i.e., interchanging the source and load in Fig. 1.…”

“…The absorber used in this case is a Laird Q-Zorb 2338 surface wave absorbing material (SWAM) [28] that is intended for attenuating surface waves with material parameters ε r = 14.4 − j0.26, μ r = 1.44 − j1.01 at 18 GHz. The complete frequency behavior of this absorber can be found in [22] and the material library of CST Microwave Studio. The weak-coupling relation in (3) is satisfied.…”

“…See Section III for illustrations and utilization of this feature. This article emanates from the master thesis [22].…”