Novel Phaseless Gain Characterization for Circularly Polarized Antennas at mm-Wave and THz Frequencies

We propose a new method of gain characterization for circularly polarized antenna arrays especially effective for mm-wave/THz frequencies. The method does not require phase-measurement or rotation of the antenna under test (AUT). It is thus ideal for waveguide-based frequency bands. In contrast to conventional methods, we use reflection-only measurements, utilizing readily available geometries, such as a PEC-plate and a PEC-dihedral corner reflector, to estimate the co- and cross-polarized gain of the AUT. Predicted error using this approach is less than 0.07 dB for the co-pol and 0.26 dB for the cross-pol for an AUT with 17 dBi gain at 100 GHz. Experimental results for a radial line slot array antenna, operating in F-band, show good agreement between the conventional method, and that proposed using phase-less method.