Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Electrical and Computer Engineering

First Advisor's Name

Stavros V. Georgakopoulos

First Advisor's Committee Title

committee chair

Second Advisor's Name

Elias A. Alwan

Second Advisor's Committee Title

committee member

Third Advisor's Name

Berrin Tansel

Third Advisor's Committee Title

committee member

Fourth Advisor's Name

Ahmed S. Ibrahim

Fourth Advisor's Committee Title

committee member

Fifth Advisor's Name

Nezih Pala

Fifth Advisor's Committee Title

committee member

Keywords

MIMO antennas, MIMO channel modeling, sub-diffraction focusing, superoscillation, SmallSat, CubeSat, small satellite, swarm, superresolution, dual-band, quad-band, isolation

Date of Defense

3-28-2023

Abstract

The scientific objective of this thesis is to develop cognitive inter-satellite MIMO communication systems for swarms of small satellites, and antenna systems that provide high resolution imaging. To achieve this objective, this dissertation proposes: (a) the first-ever-reported MIMO channel model to accurately characterize the SmallSat swarm propagation environment, (b) a novel technique to design compact multi-band multi-mode microstrip antennas (MSAs) with diversity/MIMO capabilities, and (c) the first-ever-reported practical technique to generate a far-field sub-diffraction focus in the microwave regime. Our proposed MIMO channel model is used to demonstrate that the capacity improvement provided by MIMO systems is significant, scalable, and practical in the SmallSat swarm environment. Namely, it is demonstrated that under practical constraints a (16, 16) MIMO system can provide up to 5 times the capacity of a traditional dual-polarized communication system.

Motivated by these findings, this dissertation proposes a simple and elegant technique to achieve high isolation (up to 39 dB) among the ports of compact multi-band multi-mode MSAs with diversity/MIMO capabilities by appropriately introducing slots. As compared to state-of-the-art decoupling techniques, our proposed slot-based technique has a low design complexity and a low profile. Moreover, high isolation between all pairs of ports is achieved while avoiding the introduction of additional decoupling structures and their associated losses.

Finally, by employing the discovery of superoscillations and the principles of Fourier optics, this dissertation develops the first-ever-reported (to our knowledge) practical technique to generate a far-field sub-diffraction focus in the microwave regime. Specifically, our technique produces (in theory) an arbitrary small focus using the interference of two or more appropriately designed circular arrays. As a proof-of-concept, an antenna is designed, which produces approximately a 2 times improvement in resolution over traditional sensing and imaging systems. Compared to state-of-the-art technologies, our proposed technique is expected to have significant broad impact to remote sensing (e.g., imaging and radar systems), communication and wireless power transfer systems.

Identifier

FIDC011052

ORCID

https://orcid.org/0000-0001-5436-2830

Previously Published In

N. E. Russo, C. L. Zekios and S. V. Georgakopoulos, "Decoupling Modes in Multi-Band Microstrip Patch Antennas," in IEEE Open Journal of Antennas and Propagation, vol. 2, pp. 118-125, 2021.

N. E. Russo, C. L. Zekios and S. V. Georgakopoulos, "MIMO Systems in SmallSat Swarms: System Characterization With the Introduction of a Channel Model," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 9, pp. 8276-8290, Sept. 2022.

Available for download on Monday, April 21, 2025

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