Interaction Between Internal Antenna and External Antenna of Mobile Phone and Hand Effect

In this paper, we begin by presenting a multiband antenna for mobile phone applications operating in GSM, DCS, PCS, UMTS, Bluetooth, and LTE bands. The antenna platform includes the ground plane, the battery, the camera, and other paraphernalia that the mobile phone environment typically comprises. Results show that the platform has a significant effect on the performance of the antenna, both in terms of its bandwidth and the number of its resonance frequencies. In addition, metal rings, frequently used in a mobile phone for mechanical reasons, can also have a significant influence on the performance of the antenna in the phone. Equivalent circuits and current distributions have been derived with the objective of investigating the effects of the metal ring that embrace the mobile phone. We investigate ways in which we can modify the ring so as to restore the desired performance of the antenna, which has been previously designed to operate in the phone environment but without the presence of the ring. We show how we can control the resonances of the ring by using capacitance loading and lower its Q by loading the ring resistively at a number of different strategic locations along the ring.