Mutual-Coupling Reduction in Metamaterial Substrate Integrated Waveguide Slotted Antenna Arrays Using Metal Fence Isolators for SAR and MIMO Applications

A new type of mutual coupling reduction technique is applied to metamaterial substrate integrated waveguide (SIW) slotted antenna array. The circular shaped reference SIW antenna array is constructed from Alumina substrate with dimensions of 40×5×1.5 mm
³
. Embedded in the reference antenna are 38 slots with dimensions of 2×1×1.5mm
³
. The reference SIW antenna operates over X- to Ku-bands with average isolation between the radiation slots of approximately -10Db. Isolation was increased by inserting metal fence isolators (MFIs) between the radiation slots, which increased the isolation by an average of 13dB. In addition, the antenna's impedance matching bandwidth is improved with no degradation in the radiation patterns. With MFIs the maximum gain achieved improves by ~10%. The technique is simple to implement and proposed for synthetic aperture radar (SAR) and multiple input multiple output (MIMO) applications.