I tried to track down the source of the 500 modules figure, & I am confident that 1) I've found it & 2) it's false.
It appears to be based on the assumption that the Vixen 500E will be used in Gripen. The 500 refers to the approximate number of T/R modules. Selex is absolutely explicit about this, & gives consistent names to the Vixen variants depending on TRM count, e.g. Vixen 850E. Therefore, the name is crucial to understanding the discussion. Unfortunately, references to the Vixen series are sometimes assumed to mean the 500E, the initial (& so far, only one in series production, about to enter service) model, as not everyone is aware of the existence of other models.
There are numerous references on the internet to the Vixen 500E being the basis for the new Gripen radar, but every one I have found which gives a source links back to
this Defense Industry Daily article. That article gives as its source, & links directly to (scroll down to "Per Aviation Week’s March 10/09 report")
this Aviation Week article - but when you read the AW article, you find that it
doesn't say the Vixen 500E is the basis of the new Gripen radar. It discusses the Gripen radar and the Vixen 500E (& other Selex radars) in separate paragraphs, & different contexts. It is obvious that someone at DID misread the AW article, & as is common on the internet, the error proliferated via cutting & pasting. It's sad how few people check their sources.
The highest figures are based on estimates of how many can be fitted in, derived via calculations similar to GDs, above, which gives the theoretical maximum.
Neither Selex nor SAAB has ever linked the 500E to Gripen. They have never been shown together. Gripen has shared a stand at an airshow with the larger Vixen 850E, but that is the only link between that radar & Gripen. SAAB has released CGI of Gripen with a swash plate mounted array which looks a little larger than that of the 850E. None of this is definite, & I've not found a published statement from either firm which gives a figure, but we now have this article in
Flight, in which a reputable journalist who has spoken to both SAAB & Selex says explicitly that the Vixen 1000E is the basis for the new radar.
That is consistent with all the good (as distinct from demonstrably false) previous information, & as far as I am concerned settles it. The number of TRMS is approximately 1000.