Influence of the user´s hand on mutual coupling of dual-antenna structures on mobile terminal

This paper studies the influence of the user´s hand on the mutual coupling of dual-antenna structures on a mobile terminal. The terminal consists of two planar inverted-F antennas (PIFA) on a typical 100 × 40 mm² mobile terminal chassis operating at 900 MHz, 2000 MHz, 3500 MHz and 5300 MHz bands. The hand was placed at different positions while the index finger touched different locations, and the variation of the mutual coupling was investigated. The results show that the dual-antenna structures exhibited up to 10 dB variations in mutual coupling, depending on the hand and index finger locations. The Poynting vector characteristics of the mobile terminal and free space electric field distributions can be used as tools for understanding the behavior of the mutual coupling in the dual-antenna structures in the presence of a user´s hand.