Effect of Mutual Coupling on Uniform Circular Arrays With Vector Antenna Elements

In this letter, the mutual coupling among vector antenna (VA) elements is derived based on the electromagnetic theory, where a uniform circular array with VAs is utilized as the transmit antenna array. By exploiting our result on the mutual coupling, we also analyze the electromagnetic channel from the transmitter to a receiver that measures the electric field surrounding the transmitter. As a result, we show that the number of effectively usable channels can be increased by exploiting the mutual coupling.