Measuring Dielectrics Using Shielded Loop Antennas
Description
This work is concerned with the use of shielded loop antennas to measure
permittivity as a low-cost alternative to expensive probe-based systems for biological
tissues and surrogates. Beginning with the development of a model for simulation, the
shielded loop was characterized. Following the simulations, the shielded loop was tested
in free space and while holding a cup of water. The results were then compared. Because
the physical measurements and the simulation results did not line up, simulation results
were forgone. The shielded loop antenna was then used to measure a set of NaCl saline
solutions with varying molarities. This measurement was used as a calibration set, and
the results were analyzed. By taking the peak magnitude of the input impedance of each
solution, a trend was created for the molarities. Following this measurement and analysis,
a set of unknown solutions was tested. Based on the measurements and the empirical
trends from the calibration set of measurements, the molarities of the valid unknown
solutions were estimated. It is shown that using the known molarities, permittivity can
also be calculated. Using the estimated molarities of the unknown solutions, the
permittivity of each solution was calculated. The maximum error for the estimation was
1.07% from the actual data.
permittivity as a low-cost alternative to expensive probe-based systems for biological
tissues and surrogates. Beginning with the development of a model for simulation, the
shielded loop was characterized. Following the simulations, the shielded loop was tested
in free space and while holding a cup of water. The results were then compared. Because
the physical measurements and the simulation results did not line up, simulation results
were forgone. The shielded loop antenna was then used to measure a set of NaCl saline
solutions with varying molarities. This measurement was used as a calibration set, and
the results were analyzed. By taking the peak magnitude of the input impedance of each
solution, a trend was created for the molarities. Following this measurement and analysis,
a set of unknown solutions was tested. Based on the measurements and the empirical
trends from the calibration set of measurements, the molarities of the valid unknown
solutions were estimated. It is shown that using the known molarities, permittivity can
also be calculated. Using the estimated molarities of the unknown solutions, the
permittivity of each solution was calculated. The maximum error for the estimation was
1.07% from the actual data.
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2018
Agent
- Author (aut): Yiin, Nathan
- Thesis advisor (ths): Aberle, James T., 1961-
- Committee member: Bakkaloglu, Bertan
- Committee member: Kitchen, Jennifer
- Publisher (pbl): Arizona State University