A Circularly Polarized Substrate Integrated E-Plane Waveguide Horn Antenna

Substrate integrated E-plane waveguide (SIEW) is a recently invented transmission line type that is able to guide two orthogonally polarized waves, one perpendicular and one parallel to the circuit board. This is accomplished by emulating an intact vertical metallic wall using a row of copper plated through holes as well as a copper strip that passes through all the through holes at the middle height. In this letter, it is the first time the SIEW is used to design a circularly polarized (CP) horn antenna. The antenna consists of three parts, an subminiature version A (SMA)-to-SIEW adaptor that excites the vertical and horizontal polarizations with equal amplitudes, a dielectric loaded SIEW horn antenna that efficiently radiates the vertical and horizontal polarizations with similar gain values, and an SIEW section that introduces required phase difference between the two polarizations to generate a CP wave. An antenna prototype is built and measured to validate the simulated results.