Spatial null steering microstrip antenna array

A spatial null steering microstrip antenna array comprising two concentric microstrip patch antenna elements. An inner circular antenna is used as an auxiliary element in nulling interference received by an outer annular ring antenna disposed around the inner antenna. The outer annular antenna is resonant in a higher order mode but forced to generate a right hand circularly polarized lower order (TM11) far field radiation pattern, thereby allowing co-modal phase tracking between the two antenna elements for adaptive cancellation. Each antenna element is appropriately excited by symmetrically spaced probes. Other applications of the antenna array include GPS multipath suppression, simultaneous satellite and terrestrial communications, and co-site interference suppression. Dual frequency band applications are achieved by stacked array configurations.

Patent #: 6597316 Issue Date: July 25, 2003