Miniaturised slits for decoupling PIFA array elements on handheld devices

A technique for reducing the electromagnetic coupling between planar inverted-F antennas (PIFAs), built on a compact ground plane for typical handheld devices, is presented. Novel miniaturised convoluted slits are inserted in the ground plane between two PIFAs introducing a transmission minimum in the coupling path between them and producing a significant reduction of the mutual coupling within the operating band of the antennas. The proposed slits have a small footprint and are positioned close to the edges of the ground plane, thereby occupying very little space. Simulated results as well as measurements of a fabricated prototype are presented.