Antenna diversity for mobile telephones

There have been several studies made on new diversity antennas for the mobile telephones. The main idea has been to have a built-in (planar) antenna working together with the conventional external. The purpose of this paper is to examine the concept of diversity further and to design two different concepts, one with two external antennas and one with an external antenna combined with an in-built. For evaluation a MATLAB program developed by the Center for Personkommunikation, CPK, in Aalborg, Denmark, is used. Given the radiation pattern from each antenna and the incoming field distribution from the environment, this program calculates the diversity performance of the system assuming that selection combining is used to combine the signals.