I am using Impinj Speedway Revolution readers for an installation, and I am having some trouble with collision between reader antennas. I am trying to figure out a formula for the "transmit" and "receive" functions. I have two antennas connected to the Impinj reader with a cable length of X meters. I placed them in a gate about Y meters in height. The distance (separation) between the antennas is Z meters.
I am searching for a solution by which if I changed the length of cable, the height of the gate fixed antenna and the separation between antennas, I could change the reader's values for transmit power and receive sensitivity accordingly. I need a formula that would allow me to determine the right settings, rather than going through a trial-and-error process with each reader portal. Any help your team might be able to provide would be greatly appreciated.
To answer your question, I reached out to Impinj. Here is the response from the company's engineering team:
"There are several formulas that are useful when designing a RAIN RFID system:
• Power incident on tag = reader transmit power + path loss
• Power received by reader = power incident on tag + modulation loss + path loss
• Receive sensitivity of the reader = transmit power from the reader + antenna gain + tag antenna gain + 20log10(λ/4πR), where λ = 30cm and R = the distance in meters between the reader and the tag
For more information, visit the Impinj Support Portal and download the RFID Link Budget white paper."
If any of our readers have any other relevant resources to recommend, I encourage them to post information below.
—Mark Roberti, Founder and Editor, RFID Journal