A Low-Profile Microstrip Vertically Polarized Endfire Antenna With 360° Beam-Scanning and High Beam-Shaping Capability

A novel low-profile vertically polarized planar endfire smart antenna that can achieve 360° beam-steering and high beam-shaping capability is proposed. The microstrip antenna is printed on a single thin substrate with a vertically polarized omnidirectional driven source and 36 tunable slot-integrated microstrip vertically polarized resonators (SMVR) for shaping the endfire beams. To verify the design approach, a prototype operating at the 5 GHz WLAN band is fabricated and tested. The results show that the antenna operates from 5.55 to 5.75 GHz and is capable of scanning a single endfire beam from 0° to 360° in the full azimuth plane. The scanning resolution and the maximum realized gain are 15° and 8.2 dBi, respectively. Moreover, multiple radiation pattern shapes including omnidirectional beam, dual-beams, and tri-beams can also be generated by the antenna. The overall antenna height is only $0.06~\lambda $ at 5.6 GHz. This design provides a new antenna configuration for low-profile vertically polarized endfire beam-steering and beam-shaping antenna and is promising for future wireless communication systems with lost-cost beamforming property.