When the multidomain pseudospectral time-domain(MPSTD) algorithm is used to analyze a complex problem

many types of interfaces will exist in adjacent subdomains of the whole computational domain

exchanging information between subdomains is realized by matching conditions for these interfaces.Because the characteristic variables(CV) matching condition is limited to only apply to some special types of interfaces

an improved characteristic variable(ICV) matching condition is presented for any type of interface

and interface field update relations are obtained for the ICV matching condition.Based on it

a broad wall centered- inclined slot coupler comprised two crossed rectangular waveguides is analyzed by using the MPSTD with the ICV matching condition

agreement of the MPSTD and FDTD numerical results illustrate the accuracy and validity of ICV matching condition.The analysis of a broad wall centered-inclined slot coupler of rectangular waveguide extends also application fields of the MPSTD.