Matching Items (5)
Filtering by
- Genre: Masters Thesis
Description
Modern communication systems call for state-of-the-art links that offer almost idealistic performance. This requirement had pushed the technological world to pursue communication in frequency bands that were almost incomprehensible back when the first series of cordless cellphones were invented. These requirements have impacted everything from civilian requirements, space, medical diagnostics to defense technologies and have ushered in a new era of advancements. This work presents a new and novel approach towards improving the conventional phased array systems. The Intelligent Phase Shifter (IPS) offers phase tracking and discrimination solutions that currently plague High-Frequency wireless systems. The proposed system is implemented on (CMOS) process node to better scalability and reduce the overall power dissipated. A tracking system can discern Radio Frequency (RF) Signals’ phase characteristics using a double-balanced mixer. A locally generated reference signal is then matched to the phase of the incoming receiver using a fully modular yet continuous complete 360ᵒ phase shifter that alters the phase of the local reference and matches the phase with that of an incoming RF reference. The tracking is generally two control voltages that carry In-phase and Quadrature-phase information. These control signals offer the capability of controlling similar devices when placed in an array and eliminating any ambiguity that might occur due to in-band interference.
ContributorsLakshminarasimhaiah Rajendra, Yashas (Author) / Zeinolabedinzadeh, Saeed (Thesis advisor) / Trichopoulos, Georgios (Committee member) / Aberle, James (Committee member) / Arizona State University (Publisher)
Created2021
Description
Satellite communications employs circular polarization (CP) to circumvent thewell-known phenomenon known as Faraday Rotation, where the ionosphere rotates the
horizontal and vertical polarization components resulting in signal degradation especially
at lower frequencies, i.e., VHF and L-band, and in tropical regions of the earth. Satellite circularly polarized antenna feed technology commonly employs bulkyand lossy 90-degree hybrid combiners to convert linear polarization to circular
polarization, which results in a higher noise figure for receive applications and a less
repeatable and more difficult design to tune and manufacture. This thesis aims at designing, modeling and simulating a prototype S/X dual bandCP feed/polarizer utilizing a technique known as the “Spread-Squeeze” polarizer, which
offers the advantages of compact size, ease of manufacture, and lower loss and noise
figure, relative to the current technology that often employs an external 3-dB hybrid
combiner. Ansys High Frequency Structure Simulator (HFSS), a commercial
electromagnetic modeling and simulation tool, is used for the simulations. Further, this thesis aims to characterize the performance of the dual feed hornwith respect to aperture efficiency, that is, the degree to which the feed horn illuminates
the parabolic reflector.
ContributorsCowan, Brad (Author) / Aberle, James (Thesis advisor) / Pan, George (Committee member) / Trichopoulos, Georgios (Committee member) / Arizona State University (Publisher)
Created2021
Description
Data transmission and reception has become an important aspect in day-to-day communication. With advancement in technology, it dictates the need for accurate data transmission and reception. For this very reason, wireless transceivers are employed in almost every industrial domain for numerous applications. A special concept of distributed transceivers is proven to be extremely useful in the latest technologies like Internet of Things. As the name suggests, this is a collaborative communication technique where multiple transceivers are synchronized for faster and much more reliable communication. This imposes a major challenge while designing this kind of a transceiver, as all the transceivers should be operating with carrier synchronization to maintain the proper collaboration. While there are several ways to establish this sync, this thesis emphasizes one of those techniques and tries to resolve the issue in design. The carrier synchronization is achieved using time division synchronization technique. Several challenges in implementing this technique were addressed using various models simulated in MATLAB Simulink and Keysight ADS. An in detail analysis has been performed for all the techniques used for this implementation to provide a diverse perspective.
ContributorsBoorela, Venkata Srilekhya (Author) / Zeinolabedinzadeh, Saeed (Thesis advisor) / Trichopoulos, Georgios C. (Committee member) / Aberle, James (Committee member) / Arizona State University (Publisher)
Created2021
Description
I present a trade-study of methods for a 1-port vacuum cryogenic in-situ calibration of a vector network analyzer. The three main methods I investigated in this work were: calibration using a commercial off the shelf latching electro-mechanical six way switch, a custom switch board, and a flexible multi channel stripline based printed circuit board. The test procedure was developed for use in a ground based closed-cycle cryogenic test bench to measure the reflection coefficient of a single port connectorized device under test. The device was installed in the cryogenic system alongside calibration standards. The goal of the trade study was to find which method could be used to accomplish calibration and device measurement in a single thermal cycle. Four cycles were required for industry standard open-short-load device calibration. Room temperature measurements were done with all three calibration schemes but ultimately only the single pole six throw switch proved effective enough for further testing. The cryogenic testing was carried out on an arbitrary device at ∼ 3K temperature, over a 6 GHz bandwidth. The final objective was to develop a setup and procedure for measuring the frequency and temperature dependent complex impedance of superconducting devices such as hot electron bolometer mixers, which are used for down converting the signal in the IF chain of astronomy instruments. Characterization of superconducting devices while they are at their operating temperature is challenging using traditional calibration methods. This commercial alternative is less expensive and more efficient in terms of thermal cycles and set up because it can be installed in a wide variety of cyrogenic systems.
ContributorsNeric, Marko (Author) / Trichopoulos, Georgios (Thesis advisor) / Groppi, Chris (Committee member) / Aberle, James (Committee member) / Arizona State University (Publisher)
Created2023
Description
The field of non-invasive neurostimulation techniques offer promising avenues for the treatment of various neurological and psychiatric disorders such as Parkinson's disease, migraines, chronic pain, and epilepsy. The proposed work is a novel technique for the production of high-end ultrasonic forces by interaction of gigahertz electromagnetic radiations for the purpose of neural modulation. These ultrasonic forces are created in dielectric materials such as cell membranes by the electrostrive effect, providing a potential new neurotherapeutic technique. The ability for this technique to provide neurostimulatory effects was investigated using in vitro studies of neuronal cultures and in vivo studies on sciatic nerves. Direct exposure of E18 rat cortical neurons to these EM radiations demonstrated changes in cellular membrane potential, suggesting effects could be potentially similar to direct electrical stimulation. An exploration of neuromodulatory effects to rat sciatic nerves indicates exposure produces changes to peak-to-peak muscular response. These findings suggest promising results for this new potential neuromodulation modality.
ContributorsDagher, Michael Jonathan (Author) / Muthuswamy, Jitendran (Thesis advisor) / Towe, Bruce (Committee member) / Sridharan, Arati (Committee member) / Aberle, James (Committee member) / Arizona State University (Publisher)
Created2023