Reduction of the mutual coupling between two planar inverted-F antennas working in close radiocommunication standards

This paper presents a solution to reduce the mutual coupling between two planar inverted-F antennas (PIFA's) working in close radiocommunication standards: DCS1800 (1710-1880 MHz) and UMTS (1920-2170 MHz). These antennas are positioned on the corner of a limited ground plane whose size is representative of the printed circuit board (PCB) of a typical mobile phone. Three antennas are designed and several arrangements are numerically studied. Prototypes are then fabricated and measured to validate our proposed solution which consists in inserting a suspended line between the PIFA's to neutralize the electromagnetic coupling