I initially purchased an Impinj RS-1000 development kit and, later, a ThingMagic RAIN Starter Kit. Shortly after my purchase of the Impinj kit, Impinj announce the end-of-life for the product so I moved to the ThingMagic starter kit. At $150 the ThingMagic kit was very attractive but it only supports an on-board antenna which has a sub-24 inch read range, so that reader was abandoned as well. The SparkFun Simultaneous RFID Reader – M6E Nano has been on backorder for most of the year and so, wasn’t included in the initial testing. It appears to be available as of this date.
After some further research, I purchased a ThingMagic USB Pro RFID Reader Development Kit. It has a steep price at $787 but included sample tags and a linear polarized antenna and cable. The reader, sans sample tags and antenna, can be had for $525 which is still relatively expensive but saves $242 over the cost of the kit.
I learned several things by using the USB Pro reader and antenna. The first thing I learned is that the size of the tag (basically the size of the tag’s antenna) is directly proportional to the tag’s read distance. Second I learned that a square (two-dimensionally symmetric) tag can be read more reliably in different orientations than a rectangular (one-dimensionally symmetric) tag:
| Example Square Tag | Example Rectangular Tag |
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| SMARTRAC Frog 3D RFID Wet Inlay 53mm (Monza 4QT) | SMARTRAC R6-P DogBone RFID Wet Inlay (Monza R6-P) |
| Cost per tag: $1.50 | Cost per tag: $0.65 |
Finally, I learned that the antenna that comes with the kit is linearly polarized. This means that the antenna can read over a long distance but can entirely miss a tag that isn’t oriented in a specific way or located in a specific place. As a result, I’ve invested instead in a circularly polarized antenna.
The following video illustrates the difference between the two antenna polarizations.