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A dyadic Green's function of a wedge with anisotropic impedance faces, excited by an electric dipole source, is derived for the paraxial region where the source and observation points are in proximity to the apex but widely separated. The principal anisotropy axis is the edge axis, and surface impedances parallel and transverse to this axis are considered. Following a “separation of variables” derivation, final dyadics involve eigenfunction solutions over an angular wave number and a longitudinal spectral integral, which is evaluated asymptotically assuming that k|z – z′| is large. It is observed that derived forms reveal three distinct scattering mechanisms: edge-guided waves, surface waves, and guided waves in the classical sense. Numerical simulations limited to paraxial region show that edge-guided and guided-wave terms are dominant at points away from the wedge surface, whereas surface waves are dominant near impedance surfaces. Both capacitive, inductive, and mixed (one face capacitive and the other inductive) reactive surface impedances are numerically analyzed. The resulting expressions can be used in the analysis of antennas located near the apex of a wedge and electromagnetic scattering from artificially hard and soft surfaces. [ABSTRACT FROM PUBLISHER]

We present a simple design method for the hole-slot-type cavity magnetron. Our design model includes all principal parts of magnetron, namely, the cathode, the resonant system, the interaction space, and the magnetic circuit. We first find structural, electrical, and magnetic parameters using empirical formulas. Then, using empirical values as initial guesses, we build and simulate the 3-D model of magnetron in CST Particle Studio. In CST, we show that the eigenmode solver is essential for proper mode excitation; then, we use particle tracking and particle-in-cell simulations for the desired magnetron operation. For a fast convergent result, we study the impact of design parameters on the magnetron performance. We apply this design procedure to an X-band hole-slot-type magnetron with eight resonators. We believe that our method provides designers a simple, fast, and reliable tool for hole-slot-type magnetron design. [ABSTRACT FROM PUBLISHER]

A three-dimensional dyadic Green's function is derived for electromagnetic scattering due to a point electric current source radiating in the vicinity of a wedge with anisotropic impedance and perfect electric conductor faces. The anisotropic impedance face is characterized by surface impedances along directions parallel and orthogonal to the edge axis (principal anisotropy axis). Arbitrary surface impedance is assumed in one direction only (either parallel or orthogonal to principal anisotropy axis), and vanishing impedance is assumed on the other. Assuming reactive surface impedance, the derived forms involve a summation over an angular wavenumber and a longitudinal spectral integral, which may be evaluated asymptotically to describe the fields in paraxial region, where the source and observation points are in close proximity to the apex but widely separated. The final asymptotic result reveals three different scattering mechanisms: edge-guided waves, surface waves, and guided waves in the classical sense. Numerical simulations are performed for capacitive and inductive surfaces using the asymptotic results. Simulation results are also compared to those of a commercially available electromagnetic field solver, which assumes uniform surface impedance. [ABSTRACT FROM AUTHOR]