The proposed Butler matrix could advantageously be used as a beam-forming network
for a wide antenna array.
As a beam-forming network, it is used to drive an array of N antenna elements.
A generic version of the Butler matrix used as a beam-forming network is shown in Figure 1.
A sketch of the IRIDIUM spacecraft using the Butler matrix beam-forming network is shown in Appendix C.
Sorrentino, "A novel design method for Blass matrix beam-forming networks
Since the four beams are independently formed by four separate sets of active elements and beam-forming networks
(BFN), there is no intermodulation (IM) phenomenon for this four-beam phased-array antenna.
Specifically, the microwave components include advanced multibeam antennas, shaped-beam antennas, shaped reflector antennas, an active phased-array fed and direct radiating antennas, MMIC beam-forming networks
, microwave switch matrices and solid-state power amplifiers.