Polarization diversity experiments in HF communication

We have done the experiments with horizontal polarization antenna, vertical polarization antenna and circular polarization antenna respectively, which has proved that it is difficult to build independent spatial channels of different polarizations in a scattering environment and to avoid the same frequency disturbance by using the techniques of polarization diversity. Though the theory shows that in a scattering environment an extra factor of tripling the channel capacity can be obtained, the extra energy is obtained because there are six distinguishable electric and magnetic states of polarization at a given point. According to the characteristics of radio transmission spreading in a scattering environment, the antenna of circular polarization is adopted in HF. and the results show that polarization diversity cannot distinguish spatial channels by the common radio stations and antennae.