In this paper a technique is presented on how to enhance the received signals in a near field multi-input multi-output (MIMO) environment where beam forming is not possible. This is done through the use of adaptivity on transmit. Polarization Diversity can also be implemented. This technique is based on the principle of reciprocity, is independent of the material medium in which it is transmitting, and incorporates near-field environments and multipath. The objective here is to select a set of weights adapted to each receiver to be applied to each transmitting antenna, which is a function of the user location, so that the transmitted signal at the carrier frequency may be directed to a particular receiver location while simultaneously minimizing the received signal strengths at other receiver locations. Numerical simulations have been made to illustrate the novelty of the proposed approach. A new transmission technique, based on the principle of reciprocity in a multi-input multi-output (MIMO) transmission/reception environment, which enhances the signal induced at a desired receiver while minimizing the signal strengths arriving at the other receivers from all the transmitting antennas. The objective here is to enhance the signal strength rather than the power because we are dealing with near field environments. In a near-field environment, it is necessary to treat the Poynting vector, which requires knowledge of both the electric and the magnetic fields or, in other words, the voltage and the current at the feed points of the elements of the transmit antenna array. In a near field environment, since the port currents at the antenna are determined by the electromagnetic environment, optimization of the received power is not possible for a realistic environment, as it changes with time.
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