Omnidirectional microstrip patch antenna with reconfigurable pattern and polarisation

An omnidirectional microstrip patch antenna, capable of reconfiguring both polarisation and radiation pattern is proposed. It operates with two orthogonal ±45° slanted linear polarisations and can produce two dipole-like radiation patterns, providing 360° coverage in either the horizontal or elevation plane. With appropriate steering, this enables a single antenna to provide full spherical coverage for any polarisation. The reconfiguration is realised by phase shifting, thus does not require switching elements, such as microelectromechanical system or pin diodes embedded into antenna. The basic principles of operation are discussed and validated by numerical and measured data.