Filtering by
- All Subjects: Metamaterials
- All Subjects: Frequency Selective Surfaces
- Creators: Chakraborty, Partha
- Creators: Diaz, Rodolfo E
- Creators: Huang, Liang
In the present work a remotely interrogating slot antenna inside a 60nm silver slab is designed which increases the signal to noise ratio of the original system. The antenna is tuned to resonance at 600nm range by taking advantage of the plasmon resonance properties of the metal’s negative permittivity and judicious shaping of the slot element. Full-physics simulations show the capability of detecting an 8nm particle using red light illumination. The sensitivity to the λ/78 particle is attained by detecting the change induced on the antenna’s far field signature by the proximate particle, a change that is 15dB greater than the scattering signature of the particle by itself.
To verify the capabilities of this technology in a readily accessible experimental environment, a radiofrequency scale model is designed using a meta-material to mimic the optical properties of silver in the 2GHz to 5GHz range. Various approaches to the replication of the metal’s behavior are explored in a trade-off between fidelity to the metal’s natural plasmon response, desired bandwidth of the demonstration, and
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manufacturability of the meta-material. The simulation and experimental results successfully verify the capability of the proposed near-field sensor in sub-wavelength detection and imaging not only as a proof of concept for optical frequencies but also as a potential imaging device for radio frequencies.
This thesis details the design process of a variable gain amplifier (VGA) based circuit which maintains a consistent output power over a wide range of input power signals. This effect is achieved by using power detection circuitry to adjust the gain of the VGA based on the current input power so that it is amplifier to a set power level. The paper details the theory behind this solutions as well as the design process which includes both simulations and physical testing of the actual circuit. It also analyses results of these tests and gives suggestions as to what could be done to further improve the design. The VGA based constant output power solution was designed as a section of a larger circuit which was developed as part of a senior capstone project, which is also briefly described in the paper.
The honors thesis presented in this document describes an extension to an electrical engineering capstone project whose scope is to develop the receiver electronics for an RF interrogator. The RF interrogator functions by detecting the change in resonant frequency of (i.e, frequency of maximum backscatter from) a target resulting from an environmental input. The general idea of this honors project was to design three frequency selective surfaces that would act as surrogate backscattering or reflecting targets that each contains a distinct frequency response. Using 3-D electromagnetic simulation software, three surrogate targets exhibiting bandpass frequency responses at distinct frequencies were designed and presented in this thesis.