Accordingly, the decoupling network
has to be designed, so that the interaction between control loops is minimized [20, 21].
The design of decoupling network
for arrays with complex impedance matrices can be found in 20] for a two-element array.
The low correlation between antenna elements can be achieved by adding a decoupling network
with the lumped elements, which makes the antenna design very complex [7,8].
In , a broadband decoupling network
for two tightly coupled antennas was proposed using inserting a second-order coupled resonator filter network between the coupled antennas.
In order to reduce the mutual coupling effect and integration, decoupling network
and power divider are designed together as the feeding network under the back of antenna array.
But for the return current to move vertically, it must find an alternate path, either through the decoupling network
and a nearby capacitor or component, a via used to short similar planes together, or by using the capacitance of the plane pairs.
In addition, the passive and lossless decoupling and matching networks using reactive lumped elements can be used to transform the coupled antenna ports into isolated and matched ports, for example, the design of decoupling network
for two-element arrays in [18, 19].
The key to the successful design of a capacitor decoupling network
is choosing the right capacitors and using the right layout.
Another analytical procedure in [8,9] using factorization techniques to get the required scattering matrix of the decoupling network
suggests using 180[degrees]-Hybrid to isolate two coupled antennas.