Abstract-Electromagnetic penetration through an aperture into a cavity is considered. The structure of interest comprises a slotted infinite conducting plane backed by a semielliptical channel. Three independent integral equations are used to study the structure of interest, for which analytical expressions are derived in another paper and involve summations of Mathieu functions. Numerical results from the analytical expressions for the electromagnetic fields are compared with those from integral equation methods for various cases of excitation and isorefractive materials. The agreement is excellent in all cases.

Application of adaptive integral method to scattering and radiation analysis of arbitrarily shaped planar structures," Abstract-Electromagnetic penetration through an aperture into a cavity is considered. The structure of interest is a semielliptical channel flushmounted under a metal plane and slotted along the interfocal distance of its cross-section. The channel is filled with a material isorefractive to the medium that occupies the half-space above the metal plane. Three independent integral equations are developed to compute the currents induced on the structure of interest by plane wave and line source excitations. Numerical results from the integral equation methods are compared with the evaluation of the analytical expressions, derived in a previous paper, that involve the summation of Mathieu functions. Data are presented for two polarizations, various values of intrinsic impedances and ratio between aperture width and incident radiation wavelength. Further data are presented for the bistatic radar cross-section of the structure of interest. All data obtained from the integral equation methods and the evaluations of the analytical formulas are in excellent agreement.

[1] The penetration of the electromagnetic field through an infinite slot in a conducting plane backed by a conducting-wall channel is examined. The total transverse-electric-toslot-axis field in the interior of the channel and above the conducting plane is determined by two independent integral equation methods: (1) a coupled integral equation method which can be used to determine the field in the case of a channel with an arbitrarily shaped cross section and (2) a single integral equation method which involves a Green's function specific to the shape of the backing channel. Data from the two methods are presented for the equivalent currents obtained from the integral equations, for the field near the channel-backed slot, and for the actual currents present on the conducting surfaces.

[1] The penetration of fields through an infinite slot in a conducting plane backed by a channel is examined. The total field in the interior of the channel and above the conducting plane is determined by two independent integral equation methods: (1) coupled integral equations which can be used to determine the fields for a channel with an arbitrarily shaped cross section and (2) a single integral equation which involves a Green's function specific to the shape of the channel. Data from the two methods are presented for the equivalent currents obtained from the integral equations, for the fields near the channel-backed slot, and for the actual currents present on the conducting surfaces. Methods for determining the currents and fields for the case of a transverse-electric-to-slot-axis excitation were presented in part 1. This second part focuses on the development of techniques for determining fields and currents in cases where the excitation produces a field that is transverse magnetic to the slot axis.Citation: Lockard, M. D., and C. M. Butler (2006), Penetration through a slot in a conducting plane backed by a conductingwalled channel: Transverse magnetic case, Radio Sci., 41, RS6010,

A method is presented for accurately modeling a monopole or dipole antenna fed by a coaxial line. The base of the monopole is attached to a conducting plane through which the coaxial feed line extends to the feed. The feed structures considered are easily adaptable to physically rugged forms and are simple to construct. Equivalent models for the three regions of the structure are devised and coupled integral equations for aperture fields and surface currents are formulated to enforce the boundary conditions. Three variations of the feed configuration are discussed and the reflection coefficient of the antenna feed is determined from the data obtained from the solutions of the coupled integral equations. Computed reflection coefficient values are shown to agree well with values measured on laboratory models.