Development of Micro-Machined Microwave and Terahertz Antennas

Nowadays, antennas at microwave and terahertz frequencies are used in various applications, such as mobile phones, communication systems on aircraft, ships and vehicles, medical applications, remote sensing, and so on. Therefore, demands on antenna design like small physical size, low weight, wideband and multiband, reconfigurable capabilities are increasingly required. Micro-machined technology can satisfy the needs of modern antenna designs.

This work discusses two antenna designs, micro-machined 3D foldable antenna and micro-machined THz antennas. The research in this work is to create antennas needed to extend the capabilities of existing wireless systems and provide them access to the Terahertz region of the spectrum. The core contribution of this work is using micro-machining techniques to create antennas for high-frequency applications, improve antenna performance and develop antenna integration methods.

This dissertation first shows a 3D cube antenna at 10 GHz using a silicon-based micro-machined fabrication method in which the 3D cubic shape allows IC packaging inside the cube’s hollow interior. The 3D structure is also beneficial in opening up the internal volume for other uses, such as storage for batteries. Next, this dissertation shows the HFSS simulation and micro-machined fabrication processing for the 3D antenna and measures the antenna performance, including return loss, gain, radiation pattern, and efficiency.

The second part of the dissertation designs silicon-based micro-machined THz antennas integrated with waveguide and probe housing at WR 6.5 (110-170 GHz) and WR 2.2 (325-500 GHz). These antennas are fabricated on a silicon-on-insulator (SOI) substrate with a 15-μm thick device layer for substrate modes reduction. The antenna geometry is integrated with the waveguide by the E-plane probe for THz antenna measurement and over-the-air (OTA) measurement. Simulation and measurement can demonstrate that the 15-μm SOI is a good platform for packaging and antenna integration for millimeter-wave and THz ICs. Besides, the geometry with T-wave probe housing is an integration solution with waveguide-fed devices for antenna measurement and OTA measurement. Using a single probe housing with different types of the antenna chips, the geometry in this work can generate different far fields based on variable demands using a single probe housing.