Apple knew the antenna design of the iPhone 4 could pose an issue, according to a new report. Citing a person familiar with the matter, Bloomberg reports that Ruben Caballero, a Senior Director of iPod/iPhone engineering described in the report as an antenna expert, warned company management about the potential perils of the design. According to the report, Caballero voiced his concerns in early planning meetings once the bezel antenna design had been chosen, saying that it might lead to dropped calls and would be an engineering challenge. Beyond Caballero, a separate Bloomberg source claimed that one of Apple’s carrier partners also expressed concern about the antenna, although the report does not specify the carrier’s name. Apple is expected to address the iPhone 4’s antenna issues in a press conference scheduled for 10:00 a.m. Pacific Time tomorrow.