Investigations on function for linear coupling of microwaves into slots

In this paper，the research methods for linear coupling of microwave pulses into a cavity through slots are discussed. The physical basis for the linear coupling is provided. The coupling function is defined, and the formulation of coupling function for the different polarization directions of the incident electric field is derived. To numerically solve the linear coupling problems, the finitedifference timedomain method and its modified algorithm are simply described. To measure the coupling function, this paper suggests the experimental setup which mainly consists of the vector network analyzer HP8510C. By investigating the coupling function, the phenomena of resonant and enhancement effects are observed, and the universal equation for microwave coupling into differentshaped slots