Mak was found guilty on two counts of attempting to send sensitive material to China, acting as a foreign agent without notifying the US government and making false statements to federal agents.
"I don't know so much about the law, but I feel I never intend to violate any law at all. I never intend to hurt my country," Mak told the court.
"I love this country. I don't believe I hurt this country," he said.
Mak's attorney, Ronald Kaye, said he would file an appeal within 10 days.
Mak was arrested in late 2005 after FBI agents stopped his brother and sister-in-law as they boarded a flight to Hong Kong and Guangzhou, China.
Investigators said they found three encrypted CDs in the couple's luggage that contained documents on a submarine propulsion system, a solid-state power switch for ships and a PowerPoint presentation on the future of power electronics.
Mak's defence team had argued argued that the information he gathered was not classified and was often made public at conferences that were attended by engineers from all over the world, including China.
Mak's relatives, including his wife, Rebecca Chiu, his brother, Tai Mak, sister-in-law, Fuk Li, and their son, Billy Mak, pleaded guilty following Mak's trial and conviction.
Tai Mak and Chiu, both California residents, are due to be sentenced in April and May while Fuk Li and Billy Mak were previously sentenced to time they had already served and now face deportation to China.