Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


justin_kuric_dissertation_final.pdf (13.68 MB)

ETD Abstract Container

Abstract Header

Use of Spherical Mode Expansions for In-Situ Calibration of Antenna Arrays

Kuric, Justin David
http://orcid.org/0000-0003-2547-7959
http://rave.ohiolink.edu/etdc/view?acc_num=osu1691593146309017

Abstract Details

2023, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Array signal processing algorithms for direction finding and adaptive beamforming require accurate in-situ calibration of the antenna array. Unfortunately, calibrating the array inside an anechoic chamber is often not possible because the array, or the platform it is mounted on, is too large. In addition, simulations of the array using Computational Electromagnetic (CEM) software can miss crucial information about the manufacturing defects present in the real system. The limitations of these methods has lead to the development of in-situ calibration techniques that can exploit the signals the array receives while deployed in its operational environment (i.e. Signals of Opportunity [SoOp]). In-situ calibration is advantageous because the incident signals include the effects of platform scattering and manufacturing defects without the need for an anechoic chamber. However, without any coordination between the array and the sources generating the SoOp, the transmitted signals are unknown to the array and multiple SoOp can be received simultaneously. Current methods capable of using SoOp for calibration rely on restrictive models for the array response, such as the Mutual Coupling Matrix, and are unable model the effects of platform scattering. In this dissertation, we present an in-situ calibration technique that incorporates a flexible model for the array response based on a Spherical Mode Expansion (SME). By expressing the far-field patterns of the antenna elements as a SME, we are able to model the response of an array placed in a complex scattering environment using a relatively compact representation. Because the spherical harmonics are only orthogonal over the full sphere, computing the expansion coefficients is difficult when the measurement region is limited, which is a common occurrence in in-situ calibration. We resolve this issue by employing a regularized least-squares solution and an efficient regularization parameter selection procedure. The proposed in-situ calibration technique solves for the coefficients of the SME using the signals received from multiple stationary sources while the array is in motion. This is accomplished through the use of an alternating descent algorithm that takes turns estimating the components of the incident signals and updating the coefficients of the SME. We analyze the case in which the locations of the stationary sources are known, and we also extend the proposed technique to the case when the source locations are initially unknown. The extension leverages the Direct Mapping Method (DMM) for localizing the sources with the initial array response prior to calibration. We study the performance of the proposed calibration technique using simulations of a moving antenna array and with data collected from a real array mounted to the bottom of a small aircraft during a flight over Columbus, Ohio. Results from both the simulations and the experimental data show that the proposed technique outperforms the current in-situ methods when the array is affected by platform scattering.
Inder Gupta (Advisor)
Patricia Enciso (Committee Member)
Fernando Teixeira (Committee Member)
Joel Johnson (Committee Member)
179 p.
Electrical Engineering; Electromagnetics
antenna arrays; spherical harmonics; in-situ calibration

Recommended Citations

Citations

  • Kuric, J. D. (2023). Use of Spherical Mode Expansions for In-Situ Calibration of Antenna Arrays [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1691593146309017

    APA Style (7th edition)

  • Kuric, Justin. Use of Spherical Mode Expansions for In-Situ Calibration of Antenna Arrays. 2023. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1691593146309017.

    MLA Style (8th edition)

  • Kuric, Justin. "Use of Spherical Mode Expansions for In-Situ Calibration of Antenna Arrays." Doctoral dissertation, Ohio State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=osu1691593146309017

    Chicago Manual of Style (17th edition)

osu1691593146309017
209
© 2023, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.