Design of Microwave Beam-Switching Networks

摘要

An investigation of RF beam-switching networks for creating, with a multiple-beam antenna (MBA), a set of electronically steerable antenna beams, shows that there are three main classes of network. Taking the case of a 61-beam MBA with 8 simultaneously steered beams as an example, we can describe these classes as (a) networks which can connect any one of the 8 output ports to any one of the 61 beam feeds, (b) networks which can connect the 8 output ports to any set of 8 beam feeds selected from the 61, but with a constraint imposed on the order in which the 8 ports are connected to the 8 selected feeds, and c) networks in which the set of 8 beam feeds cannot be selected arbitrarily - some fraction of the total number of conceivable interconnections cannot be completed. Networks exist in each of the three classes having very similar traffic handling performance and yet requiring a total number of switches which is very different from one class to the next. Their number is 907, 387, and 175 for the unconstrained, order-constrained and selection-constrained networks, respectively, needed to do the 61-to-8 switching job described above. The report examines the design, performance and complexity of such networks for general N and M. Included are two further measures of complexity, as well as the switching algorithm and the effect of non-uniform traffic. The results are presented as graphs, tables and formulas. (Author)