Trying to increase the range of my RFID reader/antenna for an automotive project. The range is 3in now. I need 3ft. Any ideas? I’m not an electronics guy. I would assume it would be similar to increasing the power on a CB, but much smaller level.
Any advice would be great. Thanks, Austin
Generally, it takes a special type of active RFID to read at distances over 18". Passive readers are rarely good past 12".
Article from RFIDJournal.com
It depends on the type of RFID system being used. A high-frequency (HF) reader based on the ISO 14443 air-interface protocol standard, designed for short-range transmission, has a maximum read range of about 18 inches. An active RFID system can read tags from 1,500 feet away or more, as the tags broadcast a signal and the systems are designed for longer-range applications.
Even within one type of RFID, however, there can be a wide array of read ranges. A passive ultrahigh-frequency (UHF) handheld reader has a range of about 10 feet, while a model using a beam-steerable phased-array antenna can interrogate passive tags at a distance of 600 feet or more.
Keep in mind that the reader is only half of the story. A very small passive tag with a small antenna harvests less energy from and reflects less energy back to a reader. It, therefore, has a shorter read range than a tag with a much larger antenna. I have seen small passive UHF tags that can be read by an ordinary fixed reader at a distance of only 2 or 3 feet, and I have seen passive tags that can be interrogated at a range of 80 feet.
—Mark Roberti, Founder and Editor, RFID Journal
So I guess it depends. 
Instead of RFID how about Bluetooth?
Late model vehicles have this technology. Your fob stays in your pocket and reads. I am unclear how the OEMs accomplish this…
A reader in the driver’s door for unlocking and a 2nd reader in the underside of the steering column for ignition, perhaps? Nothing says the reader has to be where the ignition key traditionally resides or that there is only one reader…
Here is one example of a semi-late-model…
http://nema.club/2014wsm/service%20highlights/books/n6w09/html/id091400108033.html
for those who wish not to click:
2014 Mazda 6 has five RF antennae: one in each front door, 1 in the front console, 1 in the rear “console”, and 1 in the rear bumper.