The planned merger between Greensboro-based RF Micro Devices Inc. and Oregon-based TriQuint Semiconductor Inc. is expected to close on Dec. 31. The planned merger between Greensboro-based RF Micro Devices Inc. and Oregon-based TriQuint Semiconductor Inc. is expected to close on Dec. 31, according to a Monday announcement. Officials from RF Micro Devices Inc. and TriQuint said the companies have received all necessary shareholder and regulatory approvals to move forward with the previously announced merger of equals.