Understanding RF Absorption by Metals in RFID Testing: A Guide

In summary, having aluminum near your RFID antenna can significantly affect its performance, causing dead zones and interference. Additionally, left hand and right hand circular polarization can cancel each other out in certain setups, so it's important to carefully consider the placement and orientation of your antennas for optimal performance.
  • #1
kirr45
1
0
Hi everyone.

I was wondering how badly aluminum affects RFID waves (860-960MHz)? Do they completely absorb, reflect, combination of the two? I'm having issues with my testing of RFID. I'm getting some dead zones and I think it could be because of the portal frame the antennas are mounted on. I have an aluminum frame connected to a 6 inch bracket antenna mount, then there antenna. Also, if you know about left hand and right hand circular polarization and in which setup they cancel each other out, that would be a big help. For example, if you have two of the same propagating, or two of the opposite propagating antennas, in which setup would be best, and which would be the worst(cancel each others performance)?

Thank you
 
Engineering news on Phys.org
  • #2
Aluminium blocks completely waves at 900MHz, with reflection, little loss and exactly zero propagation through it.

BUT things are complicated because the wavelength (0.3m) isn't very small as compared with your objects, so your radio waves are diffracted (say, like sound goes around obstacles) and do not behave at all like light does. So you cant' get a simple answer, alas.
 
  • #3
kirr45 said:
Hi everyone.

I was wondering how badly aluminum affects RFID waves (860-960MHz)? Do they completely absorb, reflect, combination of the two? I'm having issues with my testing of RFID. I'm getting some dead zones and I think it could be because of the portal frame the antennas are mounted on. I have an aluminum frame connected to a 6 inch bracket antenna mount, then there antenna. Also, if you know about left hand and right hand circular polarization and in which setup they cancel each other out, that would be a big help. For example, if you have two of the same propagating, or two of the opposite propagating antennas, in which setup would be best, and which would be the worst(cancel each others performance)?

Thank you

Welcome to the PF.

You should not have any metal near your antenna, unless it is explicitly part of the antenna structure (like the reflector and director elements of a directional Yagi antenna), or part of the antenna mast/support that is out of the antenna's pattern.
 

1. What is RF absorption by metals?

RF absorption by metals refers to the process in which high frequency electromagnetic waves or radio waves are absorbed by metallic materials, causing a decrease in the strength of the waves as they pass through the metal. This absorption occurs due to the interaction between the electromagnetic waves and the electrons in the metal, resulting in the conversion of the energy of the waves into heat.

2. Why do metals absorb RF waves?

Metals are good conductors of electricity, which means they have a high number of free electrons that can easily move within the material. When RF waves pass through a metal, the electrons are forced to move back and forth at the same frequency as the waves, causing collisions between the electrons and the metal atoms. These collisions result in the conversion of the energy of the waves into heat, leading to RF absorption by the metal.

3. What factors affect RF absorption by metals?

The amount of RF absorption by a metal depends on several factors, including the type of metal, the thickness and surface area of the metal, the frequency and intensity of the RF waves, and the temperature of the metal. Metals with high electrical conductivity and larger surface areas tend to absorb more RF waves compared to those with lower conductivity and smaller surface areas.

4. How does RF absorption by metals affect electronic devices?

RF absorption by metals can have negative effects on electronic devices, especially those that rely on RF waves for communication or operation. When RF waves are absorbed by the metal components of a device, it can cause interference or attenuation of the waves, leading to a decrease in the performance or functionality of the device. This is why electronic devices often have metal shielding to minimize RF absorption and prevent interference.

5. Can RF absorption by metals be reduced?

Yes, there are several ways to reduce RF absorption by metals. One way is by using metal coatings or films that are designed to reflect or block RF waves. Another method is to use metal alloys with lower conductivity, which can reduce the amount of RF absorption. Additionally, the design and placement of electronic devices can also affect RF absorption, and careful consideration of these factors can help minimize the impact of RF absorption on device performance.

Similar threads

Optimizing TV Antennas with Yagis: A DIY Guide for Better Reception
    • Electrical Engineering
Replies
20
Views
6K
Make 2 launchers that shoot a straw with clay at the end
    • Introductory Physics Homework Help
Replies
3
Views
425
I Understanding a practical cooling situation
    • Other Physics Topics
Replies
2
Views
1K
B Infrared Detectors & The 2nd Law of Thermodynamics
    • Thermodynamics
5
Replies
152
Views
5K
Choosing the Right Material for Shock Absorption: A Guide
    • Mechanical Engineering
Replies
1
Views
6K
Clock synchronization and relativity of simultaneity
    • Special and General Relativity
2
Replies
47
Views
6K
Alt azimuth mount for heliostat design
    • Mechanical Engineering
Replies
4
Views
3K
Considering Earth ground vs floating ground in off grid solar
    • Electrical Engineering
Replies
13
Views
4K
Simple Machines Revisited + more - making 2.5 ton lift
    • Mechanical Engineering
Replies
2
Views
1K
How should a non-cellular metal organism maintain homeostasis?
    • Biology and Medical
Replies
4
Views
4K

Hot Threads

Recent Insights

Back
Top