Cable-less measurement set-up for wireless handheld terminals

Attaching cables to mobile terminals for accurate measurements is progressively influencing the radiation characteristics with the diminishing size of the terminals. Simulations show the large influence of cables and their exact curvature on the radiation properties of mobile terminals that are small with respect to the wavelength. These results are confirmed by measurements in an anechoic chamber. As corrections for these almost irreproducible influences are hardly feasible, we propose to omit conducting cables completely. Instead, optical fibres are used for transparent transport of the RF signals. Off-the-shelf system components allow for two channels in a box of size comparable to modern small terminals. When driven at an appropriate level this set-up shows ample dynamic range for mobile radio channel sounding.