A novel method for direct impedance measurement in microwave and mm-wave bands

Abstract

A novel method for direct impedance measurement using a common vector network analyzer (VNA) is introduced. In commonly used methods impedance or admitance of a device under test (DUT) is derived from measured value of its reflection coefficient causing serious accuracy problems for very high or very low impedances. The proposed method makes possible to measure quantity directly proportional to the value of the impedance or admittance of the DUT. This enables us to accurately measure even impedances that are extremely different from value of the 50Ω reference impedance. The method can also significantly reduce effect of uncertainties of the VNA. A suitable calibration technique is suggested and fully mathematically described. The concept of the new method was verified by software simulation.