Feeding Network Synthesis Method With Arbitrary I/O Ports for Near-Field Focusing Application

A feeding network with arbitrary I/O ports and excitations is useful in wireless communication systems, especially in near-field focusing (NFF) scenarios, where the excitation weights should take the antenna position into consideration. In this paper, a new feeding network synthesis methodology based on modified QR factorization theory for arbitrary I/O ports and excitations has been proposed. By establishing the mapping relationship of the complex Givens rotation matrix with multiport devices, the transmission matrix of the orthogonal feeding network can be decomposed into complex Givens rotation matrices in cascading. Moreover, the matrix decomposition order can be further modified for the feeding network simplification. As an example, a specialized orthogonal 2×8 feeding network is synthesized for the NFF application operating at 3.5 GHz. The obtained NFF results show the potential of the feeding network design theory and testify to its extensive application scenarios.