Diagnosis of individual cell frequencies in a coupled cavity chain withoutintroducing objects into the cavity

This paper presents a new method to diagnose cell frequencies in a cavity w ithout a probe inside the cavity. The equivalent circuit model of a coupled cavity chain is used to estimate the cell frequencies and couplings betwee n cells in terms of the measured passband performance. Two assumptions used to simplify the numerical process are that the next nearest neighbor coupl ings between the cells are taken as zero and the quality factors of cells a re unchanged in the tuning procedure and defined in advance. This method ca n simplify the tuning process and makes possible the tuning of a sealed cav ity. The procedure has been verified with numerical and experimental exampl es and can be used as a guide to adjust the normal modes and field flatness in a real cavity.