Method of CRLH Antenna Impedance Measurement by Means of On-Wafer Characterization Equipment

The paper deals with a measurement method of the input impedance in the radiating section of a coplanar waveguide (CPW) Composite Right / Left-Handed (CRLH) antenna. In this respect were used the technical facilities offered by an on-wafer measurement equipment contacting the antenna feeding line. With appropriate formulas derived from the theory of the transmission lines, the resistive Rs and the reactive Xs parts of the CRLH radiating structure impedance Zs = Rs + jXs were found. The results for three antenna samples were: Zs1 (Ω) = 48.5326 - j×16.9639, Zs2 (Ω) = 48.6053 - j×16.8143 and Zs3 (Ω) = 48.1786 - j×16.3707. As it is normal, the reactive parts of the measured impedances are negative due to the CRLH line construction with series interdigital capacitors inducing left hand behavior.