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

“…Poynting vector streamlines, based on (22), are also visualized in Fig. 7 as purple and green lines.…”

“…Fig. 10(b) depicts the magnitude of S avg computed with (22) when Antenna 2 at the bottom transmits. The green lines in Fig.…”

“…The green lines in Fig. 10(b) are 40 streamlines computed with (22) that start from the port location of Antenna 1. The starting points are uniformly distributed over two lines parallel to the port of Antenna 1, i.e.…”

“…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.…”

“…The work in [11] mainly focuses on identifying coupling paths, whereas the work presented in this paper focuses on both identifying and affecting the coupling. This paper emanates from the master thesis [22].…”