Co-site interference for airborne and sea-based platforms which employ multiple radio frequency (RF) functions like electronic warfare, radar and communications may have an adverse performance effect on the on-board RF systems. For example, in a communications system, a transmitting antenna on one part of the exterior of a military or commercial vehicle may generate strong signals that may be received by a receiver, even if the main beam of the antenna is aimed well away from the receiving antenna on another part of the exterior of the vehicle. In cases in which the surface of the vehicle is metal, as may the case for a commercial or military aircraft, electromagnetic waves may propagate along the surface of the vehicle, potentially increasing the electromagnetic coupling between the transmitter and the receiver. Such signals can lead to substantial RF interference, receiver desensitization or performance degradation. This is especially true at lower frequencies (e.g., <4 GHz) where conventional radar absorbing material (RAM) isolation barriers become ineffective due to a limited barrier electrical size and material parameter roll-off (e.g., conventional magnetic RAM (MagRAM) magnetic loss properties).
Thus, there is a need for an improved system for isolating a receiving antenna from a transmitting antenna on the same platform, especially for low-frequency applications.