Gregory Mitchell

By Gregory Mitchell

This chapter will analyze the properties of electromagnetic wave propagation in anisotropic media. Of particular interest are positive index, anisotropic, and magneto-dielectric media. Engineered anisotropic media provide unique electromagnetic properties including a higher effective refractive index, high permeability with relatively low magnetic loss tangent at microwave frequencies, and lower density and weight than traditional media. This chapter presents research including plane wave solutions to propagation in anisotropic media, a mathematical derivation of birefringence in anisotropic media, modal decomposition of rectangular waveguides filled with anisotropic media, and the full derivation of anisotropic transverse resonance in a partially loaded waveguide. These are fundamental theories in the area of electromagnetic wave propagation that have been reformulated for fully anisotropic magneto-dielectric media. The ensuing results will aide interested parties in understanding wave behavior for anisotropic media to enhance designs for radio frequency devices based on anisotropic and magnetic media.

Part of the book: Antennas and Wave Propagation

By Gregory Mitchell and David Turowski

This chapter describes the results of additive manufacturing (AM) for a multi-band antenna that effectively replaces two with a single footprint. The antenna achieves distinct modes of operation by achieving flexibility between horizontal and vertical polarizations on transmit and receive at both S-band and X-band frequencies. Low dielectric constants of commercial AM materials limit current AM antenna designs. Research into the composition of high-dielectric feedstocks for AM opens the design space for 3D printed hybrid material antennas. We compare the performance of an AM antenna to the same prototype using traditional methods and materials.

Part of the book: Advanced Radio Frequency Antennas for Modern Communication and Medical Systems