Performance improvement methodology of isolation in a dual-standby mobile phone by optimizing antenna topology and position

The mutual coupling between two internal antennas using same communication band in simplified dual-standby simulation model has been researched. Furthermore, the excited current distributions on the PCB and the electric field distributions in the near field have been investigated as the cause of coupling. In terms of antenna type, PIFA type antenna was better than monopole type in the isolation viewpoint in dual-standby phone (max. 8~9 dB). Also, in terms of feed position, position 1 and 4 was the best through all positions which can be combined from 6 feed positions of Fig. 1. The coupling difference between min. and max. was 4.5 dB in monopole, 10.8 dB in PIFA. The results will be used to guidelines in the initial stage of phone design for achieving new specifications with respect to isolation of dual-standby phone.