Artificial Magnetic Conductor Measurement Techniques
Primary Faculty Mentor’s Name
Dr. Sungkyun Lim
Proposal Track
Student
Session Format
Paper Presentation
Abstract
When an electromagnetic wave is incident on a conductive material, it is reflected back with a one hundred eighty degree shift in phase. This means that if an antenna radiates too closely to a conductor and with an electric field propagation vector normal to the surface that destructive interference occurs. In fact, in order to constructively interfere an antenna must be located at a quarter-wavelength distant from the conductor. Now, in systems where profile is an issue – such as cellphones or wearable applications – this quarter wavelength thickness is much too high of a price to pay.
In order to realize a low profile – relative to some conductive material – omnidirectional antenna, a zero degree reflected phase shift is desirable. One way to produce a material with this zero degree phase shift is to make a “high impedance structure” or HIS: this is a kind of man-made material or “metamaterial” that involves imposing a design over a dielectric substrate that forces a material to have a certain inductance and capacitance that causes a high impedance. Specifically, this proposal is for a certain class of HIS called an “Artificial Magnetic Conductor” or AMC. This just means that the HIS causes the surface wave to drastically reduce the magnetic field radiation intensity – or effectively “conducting” the magnetic field.
A small unit-cell AMC has been designed, simulated in a high-frequency electromagnetic solver software CST, and a prototype has been manufactured. In order to verify the design, an experimental setup has been proposed to measure the reflected phase profile. This involved setting up two standard gain horns side by side in the far-field region relative to the design. The phase of the S21 parameter was generated in a network analyzer and exported to a Windows desktop: the S21 parameter was gathered for both a copper sheet and the AMC design itself. The values for S21 phase of the copper sheet were subtracted from the values from the AMC design: this generated the reflected phase profile.
This proposal will explore the details of this reflection phase profile measurement for this AMC including: pitfalls and errors, the finished graph, detailed processes and procedures and pictures for documentation. A comprehensive list of materials and the uses of these materials will be included for the report. This proposal will also explore other commonly used measurements made for journal paper quality work. A detailed presentation will explore the entire measurement procedure for this budding area of research, introducing the conference participants to these processes in order to improve general understanding to these unconventional measurement methods.
Keywords
AMC, EBG, metamaterial, antennas, electromagnetics
Award Consideration
1
Location
Room 2911
Presentation Year
2015
Start Date
11-7-2015 9:00 AM
End Date
11-7-2015 10:00 AM
Publication Type and Release Option
Presentation (Open Access)
Recommended Citation
Roper, Joshua and LePain, William, "Artificial Magnetic Conductor Measurement Techniques" (2015). Georgia Undergraduate Research Conference (2014-2015). 63.
https://digitalcommons.georgiasouthern.edu/gurc/2015/2015/63
Artificial Magnetic Conductor Measurement Techniques
Room 2911
When an electromagnetic wave is incident on a conductive material, it is reflected back with a one hundred eighty degree shift in phase. This means that if an antenna radiates too closely to a conductor and with an electric field propagation vector normal to the surface that destructive interference occurs. In fact, in order to constructively interfere an antenna must be located at a quarter-wavelength distant from the conductor. Now, in systems where profile is an issue – such as cellphones or wearable applications – this quarter wavelength thickness is much too high of a price to pay.
In order to realize a low profile – relative to some conductive material – omnidirectional antenna, a zero degree reflected phase shift is desirable. One way to produce a material with this zero degree phase shift is to make a “high impedance structure” or HIS: this is a kind of man-made material or “metamaterial” that involves imposing a design over a dielectric substrate that forces a material to have a certain inductance and capacitance that causes a high impedance. Specifically, this proposal is for a certain class of HIS called an “Artificial Magnetic Conductor” or AMC. This just means that the HIS causes the surface wave to drastically reduce the magnetic field radiation intensity – or effectively “conducting” the magnetic field.
A small unit-cell AMC has been designed, simulated in a high-frequency electromagnetic solver software CST, and a prototype has been manufactured. In order to verify the design, an experimental setup has been proposed to measure the reflected phase profile. This involved setting up two standard gain horns side by side in the far-field region relative to the design. The phase of the S21 parameter was generated in a network analyzer and exported to a Windows desktop: the S21 parameter was gathered for both a copper sheet and the AMC design itself. The values for S21 phase of the copper sheet were subtracted from the values from the AMC design: this generated the reflected phase profile.
This proposal will explore the details of this reflection phase profile measurement for this AMC including: pitfalls and errors, the finished graph, detailed processes and procedures and pictures for documentation. A comprehensive list of materials and the uses of these materials will be included for the report. This proposal will also explore other commonly used measurements made for journal paper quality work. A detailed presentation will explore the entire measurement procedure for this budding area of research, introducing the conference participants to these processes in order to improve general understanding to these unconventional measurement methods.
