Calibration Method for Vector Network Analyzers Using One or Two Known Reflection Standards

A novel method for the calibration of a vector network analyzer (VNA) is presented where a through connection of the VNA test ports, two known high-reflective calibration elements serving as calibration standards, and a termination of arbitrary unknown reflection are required. The latter has to be connected to both ports and may, for example, be a low-reflective load or a flush short. If it is possible to connect the same known high-reflective element to both ports, the VNA is then calibrated by the use of only one known standard. As only one two-port connection, namely a through, is required, the new method is advantageous especially for measurements in waveguides at very high frequencies if we compare it with the well-known through-reflect-line (TRL) and line-reflect-line (LRL) calibration methods where two two-port connections, namely a through and a line (TRL) or two lines (LRL) are needed. Measurements of various low- and high-reflective devices under test (DUTs) in the WR-10 and WR-03 waveguide bands agreed well with TRL and LRL reference measurements, respectively. The influence of nonideal calibration elements or of reflection variations of the unknown termination on the S-parameter measurements of DUTs has also been theoretically and experimentally investigated.