Diversity Techniques for Antenna Design

There are many diversity techniques applied to our communication products, included time, frequency, space, angular and polarization diversity techniques.

For antenna design, we often use space, angular and polarization diversity to design antenna that meet our product requirement and to enhance communication coverage. My question is: how to explain space, angular and polarization diversity, because sometimes I am getting confuse these diversity techniques?

Thanks in advance.[/b]

1) Space diversity is using multiple antennas separated in distance. You can transmit symbols which are coded on these antennas or simply repeat the same symbol on all antennas to get decorrelated multipath outputs at the reciever and combine them appropriately.

2) Angular diversity is creating beams with antenna array so that you can control the main beam direction and null directions. The idea is to transmit the symbols on different beams either coded or by just repeating.

3) Polarization diversity relates to transmitting a symbol on different polarizations. Like send a symbol 'a' on the x-polarized wave and the y polarized wave of a dual polarized antenna. Each on experiences a different channel fading and then appropriate multipath combining can be used.

-svarun

great answers do u have further materials in diversity techniques. please upload it. i desperately need them for my projects. thanks in advance and looking forward for ur reply