Northrop Grumman Corp. said Tuesday that it will re-file an application with regulators to acquire signals intelligence company Essex Corp. in an effort to give regulators more time to review the deal.

The deal was originally announced in November and Columbia, Md.-based Essex said the Los Angeles-based contractor was voluntarily withdrawing then re-filing the application to give regulators more time to review the $580 million, cash deal.

In addition to Federal Trade Commission approval, the deal also needs approval of Essex shareholders. The deal is expected to close in the first quarter of 2007, Northrop said.

Shares in Northrop closed down 65 cents to $67.70 on Dec. 29. The markets are closed Tuesday because of the funeral of former President Ford.