LZZM: An extension of the theory of the LZZ calibration technique

In this paper, the theory of the recently introduced line, offset-open, offset-short (LZZ) calibration technique is extended to develop a calibration procedure comparable to the LRRM calibration technique, the line, open, short, unknown load (LZZM). The LZZM uses as standards a known transmission line, two pairs of unknown reflecting loads and a load of unknown impedance (match) connected at one of the two ports of the vector network analyzer. Already-existing LRRM calibration procedures assume that the real part of the impedance of the load used as match standard is frequency-independent and known prior to the calibration. The LZZM compares favorably with previously reported LRRM procedures in the sense that it allows using loads of unknown and frequency-dependent impedance (real and imaginary parts) as match standard. In order to avoid redundancies in the LZZM calibration process, the impedance of the load used as the match standard has to be different from the characteristic impedance of the transmission line.