Three-Dimensional SIW-Driven Microstrip Antenna for Wideband Linear and Circular Polarization Applications

This letter presents a class of microstrip antenna driven by substrate-integrated waveguide (SIW) in three-dimensional (3-D) topology for wideband linear and circular polarizations. They are composed of the horizontal radiation patches and vertical or 3-D SIW feeding network. This LEGO-style architecture explores a novel perspective for 3-D integrated patch antenna, thereby offering a flexible spatial power distribution for low-cost and -weight applications. The SIW vertically cavity-coupled linearly polarized patch antenna presents numerous advantages, such as wide bandwidth, low cross-polarization level, and symmetrical radiation pattern. For the circularly polarized counterpart, improved axial-ratio bandwidth is obtained by the 3-D SIW feeder through a desired sequential-rotation excitation of a 2 × 2 H-shape patch array antenna.