Increasing Isolation Between Colocated Antennas Using a Spatial Notch

This letter presents an antenna configuration to achieve a coupling reduction between colocated antennas. Application of an adaptive spatial notch enables this functionality. Analytical results are obtained, which show good resemblance to simulated and measured results, performed on a prototype manufactured to operate around 2.5 GHz. Coupling reduction of 50 dB has been measured. The antenna impedance is also influenced because of this configuration and shows an S₁₁ better than - 15 dB at the frequency of interest. In addition, the radiation pattern of both antennas is influenced. This can be seen as an advantage or a disadvantage, depending on the application.