In view of the poor time-efficiency and generality of the traditional macro cell method

an improved macro cell method(IMCM)is proposed

capable of extracting the dispersive properties of any 1D reciprocal artificial periodic transmission line(APTL)with finite periodicity.Key to the IMCM lies in that the multiple-root problem of the initially extracted phase shift constant is transferred to the problem of judging the starting frequency of the phase unwrapping

making it easy to determine the uniquely correct phase shift constant.Since the electromagnetic coupling effects among unit cells of a periodic s

tructure are rigorously considered in the IMCM

both the dispersion and Bloch impedance characteristics can be accurately and effectively extracted with simulation or measurement only once

however strong the coupling intensity is.As examples

the proposed IMCM is applied to extract the dispersive properties of the classical reciprocal asymmetric microstrip composite right-/left-handed transmission lines(CRLHTLs)in the unbalanced and balanced states

and the extraction results are compared to those from the traditional eigenmode method

unwrapping method(UPM)and single cell method.Furthermore

S

parameters of the microstrip CRLHTL are retrieved using the extraction results of the IMCM and the UPM

and the former

S

parameters coincide perfectly with the full-wave results

confirming the accuracy of the IMCM.