Investigation of impedance-matching techniques for infrared antennas

Search for this publication on Google Scholar
Moreno Cleves, C. (2020). Investigation of impedance-matching techniques for infrared antennas. Unc Charlotte Electronic Theses And Dissertations.
Download PDF

Analytics

54 views ◎
13 downloads ⇓


Abstract

In this study, we used scattering-scanning near-field optical microscopy (s-SNOM) to experimentally characterize several structures relevant to infrared (IR) antenna technology, by measuring the electric near-field strength as a function of position on metallic antennas and transmission lines. Having spatially resolved measurements of electric field amplitude allows assessment of the wave impedance at any location on a standing-wave structure. We improved the usual s-SNOM data-processing method using a principal-components decomposition to allow unambiguous phase retrieval. We demonstrated the efficacy of this technique on IR bow-tie antennas of continuous and discrete designs, allowing comparison of their polarization dependence and spatial response distribution. This phase-retrieval procedure was used throughout our investigations. An IR sensor of particular interest is the antenna-coupled metal-oxide-metal (MOM) diode, which rectifies IR-frequency current waves collected by the antenna to produce an output voltage proportional to the incident irradiance. These sensors are appealing because they have a fast response and do not require cryogenic cooling. IR antennas have a typical impedance in the range of tens of Ohms at resonance, while MOM diodes have impedance in the range of thousands of Ohms. This impedance mismatch is a limiting factor in the detection sensitivity that can be achieved with antenna-coupled MOM diodes. To address this issue, we studied two impedance-matching techniques. The first is based on the fact that a MOM diode under DC bias exhibits a change in its dynamic resistance. We obtained measurements that demonstrate modification of IR-frequency current waves using diodes contained in the antenna structure. The ability to tune the operating point of a MOM diode and thereby modify antenna or transmission-line impedance at IR frequencies offers the possibility of active impedance-matching networks. The second technique we investigated involved tailoring of the feed-point geometry to obtain an antenna with higher impedance that offers better matching. We designed, fabricated and demonstrated several new IR-antenna designs that have impedance in the range of 1000 Ohms. This new class of antennas stands to improve signal-transfer efficiency to high-impedance IR sensors such as MOM diodes.

Details
Author

Moreno Cleves, Camilo

Title

Investigation of impedance-matching techniques for infrared antennas

Physical Description

1 online resource (104 pages) : PDF

Date

2020

Degree Granting Institution

University of North Carolina at Charlotte

Abstract

In this study, we used scattering-scanning near-field optical microscopy (s-SNOM) to experimentally characterize several structures relevant to infrared (IR) antenna technology, by measuring the electric near-field strength as a function of position on metallic antennas and transmission lines. Having spatially resolved measurements of electric field amplitude allows assessment of the wave impedance at any location on a standing-wave structure. We improved the usual s-SNOM data-processing method using a principal-components decomposition to allow unambiguous phase retrieval. We demonstrated the efficacy of this technique on IR bow-tie antennas of continuous and discrete designs, allowing comparison of their polarization dependence and spatial response distribution. This phase-retrieval procedure was used throughout our investigations. An IR sensor of particular interest is the antenna-coupled metal-oxide-metal (MOM) diode, which rectifies IR-frequency current waves collected by the antenna to produce an output voltage proportional to the incident irradiance. These sensors are appealing because they have a fast response and do not require cryogenic cooling. IR antennas have a typical impedance in the range of tens of Ohms at resonance, while MOM diodes have impedance in the range of thousands of Ohms. This impedance mismatch is a limiting factor in the detection sensitivity that can be achieved with antenna-coupled MOM diodes. To address this issue, we studied two impedance-matching techniques. The first is based on the fact that a MOM diode under DC bias exhibits a change in its dynamic resistance. We obtained measurements that demonstrate modification of IR-frequency current waves using diodes contained in the antenna structure. The ability to tune the operating point of a MOM diode and thereby modify antenna or transmission-line impedance at IR frequencies offers the possibility of active impedance-matching networks. The second technique we investigated involved tailoring of the feed-point geometry to obtain an antenna with higher impedance that offers better matching. We designed, fabricated and demonstrated several new IR-antenna designs that have impedance in the range of 1000 Ohms. This new class of antennas stands to improve signal-transfer efficiency to high-impedance IR sensors such as MOM diodes.

Genre

doctoral dissertations

Subjects--Topics

Electrical engineering
Optics
Physics

Degree

Ph.D.

Keywords

Antenna
Impedance Matching
Infrared
Nanoantenna
s-SNOM

Subject Area

Optical Science & Engineering

Advisor(s)

Boreman, Glenn

Committee Members

Hofmann, Tino
Astratov, Vasily
Smith, Kathryn

Degree Note

Thesis (Ph.D.)--University of North Carolina at Charlotte, 2020.

Rights Statement

This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). For additional information, see http://rightsstatements.org/page/InC/1.0/.

Rights Holder Information

Copyright is held by the author unless otherwise indicated.

Identifier

MorenoCleves_uncc_0694D_12618

Permalink

http://hdl.handle.net/20.500.13093/etd:2064