| The terahertz (.1-10 THz) and submillimeter (.3-3 THz) spectra offer promising technology useful to a wide variety of fields. The medical and pharmaceutical industries hope to use these wavelengths to image biological tissue and to determine the chemical composition of drugs, the Department of Defense and Homeland Security would detect chemical and biological warfare agents, and astronomers would learn more about interstellar media. As science probes into the terahertz region (THz), there is a need for more precise micromachining techniques to fabricate rectangular waveguide circuits and their components. Conventional CNC (computer numerical controlled) machining has been shown to be adequate for fabricating simple circuits and structures (i.e., typically >100 mum features and < 3:1-2:1 aspect ratios), and is the current commercial method of choice. Unfortunately, as the wavelength decreases so does the skin depth and the critical dimensions of the circuits. Therefore, as technology pushes to higher frequencies conventional machining may no longer be able meet the RF performance needed for such circuits. For terahertz technology to mature a new machining method capable of fabricating smaller features and greater aspect ratios is needed to form sophisticated circuits and components such as directional couplers, filters, phase shifters, and twists. Micromachining techniques have been shown to have the necessary precision to fabricate accurate submillimeter circuits and structures; however, few submillimeter circuits created by these techniques have been tested and/or integrated into existing systems. This thesis develops a new photoresist based UV LIGA (Lithographie, Galvanoformung, Abformung) process to develop sophisticated circuits and components (>15:1 aspect ratios) that are ready to play with existing terahertz systems. |
