Update 15th May 2018 — Between writing the first draft of this article and pushing the big red “Publish” button, the prices for all of the items mentioned here have already changed (downwards), so please refer to the u-blox AG online site for the latest, up-to-date pricing for your area.
u-blox AG, the Swiss company famous in hobby circles mainly for their excellent (and cheap) little GPS modules, have started selling two new standalone WiFi modules, the NINA-W101 (external antenna connector) and the NINA-W102 (module mounted antenna). The W101 is priced at $US 8.75 and the W102 is $US 9.48, direct from u-blox in bulk (250, or more). While that price is fairly competitive for an ESP32 module (assuming that the one-off price isn’t too far out of that particular ballpark), the cost of the development board is a bit excessive, at US$ 99 (again, available directly from u-blox AG’s on-line shop).
The antenna on the W102 model (shown above) is neither the older SMD-chip type nor the PCB trace type. It seems to be a custom made planar inverted-F antenna (PIFA), distinct from the existing ESP modules in that it stands over 1mm higher than the RF shield on the module. u-blox AG provide suggested sizing for orientation and ground-plane sizing in their datasheet.
The NINA-W10 series data-sheet makes interesting reading and, although the u-blox document doesn’t come right out and say “this is an ESP32”, it doesn’t keep it a secret, either (on a couple of the pages there’s a footnote reference saying “See the Espressif ESP32 Datasheet for…).
Although neither of these modules is particularly hobbyist friendly (ref the solder-side of the W102 module in the photo, above), many IOT designers will be excited to see that they are FCC approved for the U.S. (and RED/FCC-equivalent for many other countries, too) and that u-blox AG offer support for integrating the modules into an end product as a “grantee” (if you understand the FCC process that last part will hopefully make sense to you).
In the same “Short Range, WiFi” product category are the closely related NINA-W131 and W132 products which appear to be almost identical, except that Bluetooth isn’t available. Details on these two modules are a little sparser than the W101/102 variants.