Optimal Design of Multi-beam Antenna Array by the Method of Maximum Power Transmission Efficiency

This letter presents an optimization procedure for the design of mutli-beam antenna array (MBAA) by the method of maximum power transmission efficiency (MMPTE). The process is demonstrated through the design of a MBAA for indoor wireless access point. The MBAA operateing at 6GHz consists of four E-shaped patch elements and is required to generate four squint beams in different directions simultaneously. For this purpose, the MBAA under design is set as transmitting and four test receiving antennas are introduced as receiving and positioned in the desired directions where the beams need to be produced. By maximizing the power transmission efficiency (PTE) between the MBAA under design and the test receiving antenna array, an optimized distribution of excitations for the MBAA can be obtained and then realized by a simple feeding network. To increase the beamwidth, the E-shaped patch element is set to operate in a higher-order mode state in which two adjacent beams can be generated. The two adjacent beams from a single patch element are shown to merge together to form a wide beam pattern after the optimization of the array with MMPTE.