In California, transit-oriented developments (TODs) are encouraged by state, regional, and local governments to reduce greenhouse gas emissions, alleviate the housing affordability crisis, and address the mobility and shelter needs of transit-dependent populations. In addition, housing near transit stations is expected to contribute positively to location affordability, measured as the share of household income spent on combined transportation and housing costs. While considerable literature has focused on the impact of TODs on stimulating economic growth and reducing greenhouse gas emissions, there is scant research examining the extent to which TODs contribute to equitable development. This dissertation, consisting of three studies, examines (1) the impact of TODs on location affordability for households living near transit stations over time and (2) the extent to which local governments in Southern California promote equitable development in TODs through development regulations, policies, and programs.

Focusing on TODs’ impact on location affordability, I use a quasi-experimental design with propensity score matching to compare changes in local affordability between neighborhoods near new rail stations and those without rail service. Findings reveal that while rail station construction does not significantly affect affordability, the operation of rail transit may improve location affordability in the early operating years. However, lower-income households in TOD areas are more cost-burdened and may experience decreasing affordability over time. Examining governmental efforts in promoting equitable TODs, I analyze 19 TOD specific plans through content analysis. Findings indicate that local TOD planning has yet to prioritize social equity and the needs of transit-dependent populations. Although common strategies include increasing multifamily housing, providing affordable housing near transit, and community engagement, their implementation varies widely across cities. Furthermore, I evaluate the efficacy of the Transit-Oriented Communities Affordable Housing Incentive Program adopted by the City of Los Angeles to promote affordable housing production near transit. Through spatial analysis and interviews with key stakeholders, this program is shown to be effective due to its significant regulatory relief and streamlined entitlement process.

This dissertation emphasizes a stronger focus on social equity within TOD policies and programs. It suggests that local governments should not only mandate or prioritize affordable housing provisions through specific plans or incentive programs like the TOC program but also integrate the most disadvantaged groups—often low-income and transit-dependent— into the planning and decision-making processes to truly address their needs. The research method used in this dissertation could also serve as an evaluative tool that local and regional governments could use to identify the strengths and weaknesses of existing policies and encourage policy changes in facilitating equitable development outcomes near transit stations.

We investigate the directive radiation at 1550 nm from an optical leaky wave antenna (OLWA) with semiconductor perturbations made of silicon (Si). We study the radiation pattern dependence on the physical dimensions, number of perturbations and carrier densities in these semiconductor perturbations through optical excitations at a visible wavelength, 625 nm. In this detailed theoretical study we show the correlation between the pump power absorbed in the perturbations, the signal guided in the waveguide and the radiation through leakage. To overcome the limited control of the radiation intensity through excess carrier generation in Si, we present a new design with the OLWA integrated with a Fabry-Pérot resonator (FPR). We provide analytical and numerical studies of the enhanced radiation performance of the OLWA antenna inside the FPR, and derive closed-form formulas accounting for LW reflection at the edges of the FPR. A discussion on the constructive and destructive radiation by the direct and reflected leaky waves in the FPR resonator is provided. Results shown in this paper exhibit 3 dB variation of the radiation and pave the way for further optimization and theoretical developments.

We provide analytical modeling and the detailed procedure that is used in recently proposed arbitrary waveform generation technique by using MEMS digital micro-mirror arrays. We estimate the achievable temporal resolution, repetition rate, modulation index and the rise/fall times of the final waveform as figure of merit in the proposed systems. We show that reducing the diffraction limit via increasing the ratio of beam size to lens focal length (>0.075) and the spatial modulation down to single mirror pitch size (10.8μm), waveforms up to 18GHz repetition rates with >90% modulation index and <100ps rise times are achievable. Theoretical calculations are compared with experimental generation of 120MHz square waves and 160MHz sawtooth waves and obtained good agreement.