A Cross-Joint Vivaldi Antenna Pair for Dual-Pol and Broadband Testing Capabilities

The non-standalone 5G antenna wireless communication standard and devices operating under Wi-Fi 5, 6, and 6E operate at the 3 GHz frequency bands and above. With the increasing demand for these devices and technologies, it is crucial to test them rapidly and economically for commercial usage. This paper presents a dual-polarized Vivaldi antenna for the over-the-air (OTA) measurement of wireless communication devices used in the 3-7 GHz band. The dual-polarization performance is realized by vertically intersecting two planar Vivaldi antennas and soldering them at the back end. A three-step 1/4 wavelength balun is applied to the input for the wideband impedance matching of the antenna, which is attached to a Teflon holder for easy mounting. It has excellent performance and is designed to be manufactured at low cost. The fabricated antenna was tested in an anechoic chamber and showed S11 less than -10 dB from 2.63-7.15 GH, and a realized gain of more than 5 dBi from 3 GHz and above. A measured half-power beam width of more than 60° was realized with symmetric E/H-plane. Much of the required symmetry was achieved with the designed Teflon holder. The antenna has a measured cross-polarization discrimination of better than 15 dB across the entire operating bandwidth.