The intrinsic Josephson junctions in the high transition temperature superconductor Bi2Sr2CaCu2O8+δ (BSCCO) have shown great potential for oscillators emitting in the terahertz frequency. The radiation frequency satisfies the conditions for both the ac Josephson effect and for a mesa cavity resonance mode. The observed angular dependence of the emissions from some mesa imply that the ac Josephson effect plays the primary role in a dual source radiation mechanism. But the integrated emission power had generally been significantly below the 1 mW level suitable for many applications. This output power can be enhanced by a suitable design of an array of suitably shaped mesas that are all within a wavelength of each other so that their combined output is coherent. One such tightly packed array consists of concentric annuli. Here we calculate the angularly independent modes of thin annular microstrip antennas, with the ratio of the inner to the outer radii varying from 0.1 to 0.9. We then calculate the angular distribution of the emission power arising from the annular cavity modes and from the uniform ac Josephson current source at the frequencies of the cavity modes. We also calculate the five leading wavefunctions with the lowest order angular dependence for those annuli.
Master of Science (M.S.)
College of Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Bonnough, Sheila, "Terahertz Emission from the Intrinsic Josephson Junctions of High-Symmetry Thermally-Managed Bi2Sr2CaCu2O8+d Annular Microstrip Antennas" (2018). Electronic Theses and Dissertations, 2004-2019. 6265.