Fast and broadband computation of the Green's function in a cavity resonator of irregular shape using an imaginary wave number extraction technique.

A semi-analytical approach for rapid calculation of the Green's function inside a cavity of irregular shape over a broad range of frequency is presented. The method is based on the extraction of the Green's function at an imaginary wave number from itself to obtain a rapidly convergent hybrid spatial-spectral expansion of the Green's function. The method is applied to a V-grooved cavity, and the results are compared with the integral equation method.