I’ve heard that Impinj developed such a tag, but I can not find any information about it.
—Robert
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Impinj developed a near-field communication (NFC) tag that it says can be read through water. Like a high-frequency (HF) tag—which features a coil so the tag forms an electromagnet field with the coiled antenna in the read—the near-field tag couples with the reader antenna, rather than reflecting back a signal. One benefit of this is the ability to read a tag through water. Impinj has demonstrated this ability by dropping tags into liquid and reading them. But this tag is not the same as standard ultrahigh-frequency (UHF) tags, which have a 25-foot read range. A near-field tag has a very short read range—approximately a foot or so.
—Mark Roberti, Editor, RFID Journal