RFID - which technology to use for ~2m range, low bandwidth, multi-tag, readonly tags

Hi all,

I'm researching RFID for an application which would require the following:

* Detection range of about 2m (actually, what I'm really interested in is detecting any tag leaving through a door, kind of like the ones in commercial stores for security
* Need to be able to detect multiple tags at a time
* No need to write to them; just read an ID
* Passive tags

So far, it seems that UHF is the frequency I should be targeting (due to the range), but all readers are more than S200 (and I want to make this cheap).

Does anybody know of a cheaper reader in the market, or some other technology (maybe a weird antenna design) that would allow me to use the cheaper readers (125KHz or simillar)?

Thanks in advanced for any reply,

- Nicolas.

Did you find any solution for this?