This thesis presents a multi-phase injection locking (IL) technique and its application in the locking range extension in multi-phase injection locking oscillators (ILOs) for Terahertz (THz) signal generation. The proposed technique can significantly increase the frequency locking range of a multi-phase injection locking oscillator compared to the conventional single-phase injection locking scheme. Based on the multi-phase IL technique and sub-harmonic ILOs, an “active frequency multiplier chain” architecture and a multi-ring system layout topology are also proposed to achieve scalable THz signal generation. As proof of concept, a cascaded 3-stage 3-phase 2nd-order sub-harmonic ILO chain is implemented in the IBM 9HP SiGe BiCMOS process. The design achieves a maximum output power of -16.6dBm at 498GHz, a phase noise of -87dBc/ Hz at 1MHz offset, and a total 5.1% frequency tuning range from 485.1GHz to 510.7GHz, which is the largest frequency tuning range among all the reported silicon-based THz oscillator sources in the 0.5THz band.

Searching for objects in physical space is one of the most important tasks for humans. Mobile sensor networks can be great tools for the task. Transient targets refer to a class of objects which are not identifiable unless momentary sensing and signaling conditions are satisfied. The transient property is often introduced by target attributes, privacy concerns, environment constraints, and sensing limitations. Transient target localization problems are challenging because the transient property is often coupled with factors such as sensing range limits, various coverage functions, constrained mobility, signal correspondence, limited number of searchers, and a vast searching region. To tackle these challenge tasks, we gradually increase complexity of the transient target localization problem such as Single Robot Single Target (SRST), Multiple Robots Single Target (MRST), Single Robot Multiple Targets (SRMT) and Multiple Robots Multiple Targets (MRMT). We propose the expected searching time (EST) as a primary metric to assess the searching ability of a single robot and the spatiotemporal probability occupancy grid (SPOG) method that captures transient characteristics of multiple targets and tracks the spatiotemporal posterior probability distribution of the target transmissions. Besides, we introduce a team of multiple robots and develop a sensor fusion model using the signal strength ratio from the paired robots in centralized and decentralized manners. We have implemented and validated the algorithms under a hardware-driven simulation and physical experiments.

This research discusses the design, fabrication, integration, and characterization of micromachined millimeter-wave components and a signal source for THz multiplier source using the deep reactive ion etching technique. A wide range of advanced micromachined millimeter-wave components are proposed and fully validated with the measurement. These micromachined millimeter-wave passives include: the W-band straight and meander waveguides, W-band three-pole filter, waveguide hybrid and power divider, a novel CPW-to-waveguide transition and filter, and a novel cavity resonator for 60-GHz reconfigurable applications. The proposed THz multiplier source is a broadband 900-GHz silicon micromachined two-anode frequency tripler with the state-of-the-art performance. The research results enable the silicon micromachining technique to build low-loss and low-cost millimeter-wave components and THz signal sources.