Development of micromachined millimeter-wave modules for next-generation wireless transceiver front-ends

This thesis discusses the design, fabrication, integration and characterization of millimeter wave passive components using polymer-core-conductor surface micromachining technologies. Several antennas, including a W-band broadband micromachined monopole antenna on a lossy glass substrate, and a Ka-band elevated patch antenna, and a V-band micromachined horn antenna, are presented. All antennas have advantages such as a broad operation band and high efficiency. A low-loss broadband coupler and a high-Q cavity for millimeter-wave applications, using surface micromachining technologies is reported using the same technology. Several low-loss all-pole band-pass filters and transmission-zero filters are developed, respectively. Superior simulation and measurement results show that polymer-core-conductor surface micromachining is a powerful technology for the integration of high-performance cavity, coupler and filters. Integration of high performance millimeter-wave transceiver front-end is also presented for the first time. By elevating a cavity-filter-based duplexer and a horn antenna on top of the substrate and using air as the filler, the dielectric loss can be eliminated. A full-duplex transceiver front-end integrated with amplifiers are designed, fabricated, and comprehensively characterized to demonstrate advantages brought by this surface micromachining technology. It is a low loss and substrate-independent solution for millimeter-wave transceiver integration.Ph.D.Committee Chair: John Papapolymerou; Committee Chair: Manos Tentzeris; Committee Member: Gordon Stuber; Committee Member: John Cressler; Committee Member: John Z. Zhang; Committee Member: Joy Laska

Master of Science

thesisCarnallite recovery by reverse flotation of halite with dodecyl morpholine (DDM) as collector has been applied in industry. Despite successful use in industry, the surface chemistry for halite flotation with DDM collector is not clear. Therefore the major objective of this thesis research was to examine the flotation chemistry in detail and understand the nature of the interaction between the DDM collector and the soluble salt minerals, halite (NaCl), sylvite (KCl), and carnallite (KMgCl3 .6H2O). After the introduction in Chapter 1, the flotation response of halite, sylvite and carnallite is reported as evaluated using microflotation. The results indicate that both NaCl and KCl can be floated using DDM as a collector from saturated solution. However, flotation of carnallite was not achieved at these or higher concentrations. FTIR analysis by the DRIFT technique showed that DDM selectively adsorbed at the surface of NaCl and KCl. In Chapter 3, the chemical features of dodecyl morpholine were evaluated by surface tension measurements for halite-, sylvite-, and carnallite-saturated solutions. The precipitation concentration was determined by turbidity measurements. In addition, the zeta potential of the collector colloid was also determined at different pH values. In Chapter 4, the wetting characteristics for NaCl, KCl and carnallite are reported. Contact-angle measurements as a function of DDM concentration indicate that, when the DDM concentration increased to 2 × 10-6 M, an increase in contact angle was observed at the surface of NaCl and KCl. Bubble attachment-time experiments indicate that there is a critical concentration at which effective attachment occurs. In Chapter 5, initial efforts to study the interfacial water structure using molecular dynamic simulation (MDS) are described. The simulation results indicate that the carnallite surface was completely hydrated. Therefore, the collector molecules or the collector colloid cannot replace interfacial water molecules at the surface of carnallite, and the carnallite particles remain hydrophilic during flotation with DDM. The water residence time at the NaCl surface, about 30 ps, is longer than the water residence time of 20 ps at the KCl surface but very small when compared with that of carnallite. The water residence time at the carnallite surface is longer than the simulation time of the water/carnallite system (1000 ps). This appears to be the major reason that carnallite cannot be floated using DDM or DDA as collector for that matter

Signatures of Self-Interacting Dark Matter in the Matter Power Spectrum and the CMB

We consider a self-interacting dark matter model in which the massive dark photon mediating the self-interaction decays to light dark fermions to avoid over-closing the universe. We find that if the model is constrained to explain the dark matter halos inferred for spiral galaxies and galaxy clusters simultaneously, there is a strong indication that dark matter is produced asymmetrically in the early universe. It also implies the presence of dark radiation, late kinetic decoupling for dark matter, and a suppressed linear power spectrum due to dark acoustic damping. The Lyman-$\alpha$ forest power spectrum measurements put a strong upper limit on the damping scale and the model has little room to reduce the abundances of satellite galaxies. Future observations in the matter power spectrum and the CMB, in tandem with the impact of self-interactions in galactic halos, makes it possible to measure the gauge coupling and masses of the dark sector particles even when signals in conventional dark matter searches are absent.Comment: 5 pages, 7 figures, published version in PL

The Heine-Stieltjes correspondence and a new angular momentum projection for many-particle systems

A new angular momentum projection for systems of particles with arbitrary spins is formulated based on the Heine-Stieltjes correspondence, which can be regarded as the solutions of the mean-field plus pairing model in the strong pairing interaction G ->Infinity limit. Properties of the Stieltjes zeros of the extended Heine-Stieltjes polynomials, of which the roots determine the projected states, and the related Van Vleck zeros are discussed. The electrostatic interpretation of these zeros is presented. As examples, applications to n nonidentical particles of spin-1/2 and to identical bosons or fermions are made to elucidate the procedure and properties of the Stieltjes zeros and the related Van Vleck zeros. It is shown that the new angular momentum projection for n identical bosons or fermions can be simplified with the branching multiplicity formula of U(N) supset O(3) and the special choices of the parameters used in the projection. Especially, it is shown that the solutions for identical bosons can always be expressed in terms of zeros of Jacobi polynomials. However, unlike non-identical particle systems, the n-coupled states of identical particles are non-orthogonal with respect to the multiplicity label after the projection.Comment: 14 pages LaTeX with no figur