Senior engineer and antenna expert, Ruben Caballero, voiced concerns over the iPhone 4's antenna to Steve Jobs before the handset's design specifications were finalised, claims Bloomberg.

The news service has spoken to two people, which it is not able to identify, who have cast doubt over the way Apple handled the early days of the iPhone 4. According to one of them, Caballero informed Apple’s management the device’s design may cause reception problems, but was ignored.

The other anonymous source stated that one of Apple's partner carriers also spoke about reception issues before the launch date of 24 June.

Naturally, Apple declined to comment, and refused access to Caballero himself. But, considering that share prices are dropping and a hastily arranged press conference is due tomorrow (Friday 16 July), these revelations couldn't have come at a worse time for the company.