Indoor propagation measurements at 2.45GHz and 17GHz

Microwave propagation measurements taken within an indoor environment are presented which illustrate the advantages to be obtained by using circularly polarized signals rather than linearly polarized signals. Particular emphasis has been placed on the cross-polarization effects within multipath channels. Two frequencies were investigated, namely 2.45GHz and 17GHz, which were chosen to correspond with those recently designated for indoor telemetry. Data are presented which quantify the degree of cross-polarization between the two modes of circular polarization, which has implications for the development of multi-channel systems or the implementation of polarization shift keying. Comparative measurements are presented for propagation at the two frequencies specified within a building which has a significant degree of shielding incorporated into the fabric of the structure. It is intended that the measurements obtained, together with a more rigorous analysis of the behaviour of circulary polarized signals on reflection, will enable a more accurate model to be developed for simulating indoor channel performance using circularly polarized signals.