A former employee of a New Jersey-based defence contractor has been found guilty of taking US military technology trade secrets from his employer and exporting them to his native China.

Sixing Liu, also known as Steve Liu, worked for Space & Navigation, a New Jersey division of New York-based L3 Communications. Liu, who had lived until recently in Flanders, New Jersey, was arrested at his home in Deerfield, Illinois, in March 2011 and accused of taking restricted military data and presenting them at two conferences in China the previous northern autumn.

Prosecutors argued the technology was proprietary and could be used for target locators and other military applications.

A federal jury in Newark on Wednesday found Liu guilty on nine counts, including exporting defence-related data without a licence, possessing stolen trade secrets and lying to federal agents. He was acquitted on two counts of lying to federal authorities about one of his visits to China.

Liu, 49, was ordered held until his January 7 sentencing. He faces more than 20 years in prison and possible deportation.

Liu’s lawyer, James Tunick, said they would file an appeal.

According to the indictment, Liu took a personal laptop computer to conferences on nanotechnology in Chongqing in 2009 and Shanghai in 2010 and, while there, gave presentations that described the technology he was working on, in violation of US laws that prohibit exporting defence materials without a licence or approval from the Department of State.

Returning from Shanghai in November 2010, Liu lied about his involvement in the conference when questioned by customs officials at Newark Liberty International Airport, prosecutors said.

“The United States spends billions of dollars each year on research and development, and this ‘intellectual capital’ is very attractive to others,” said Michael Ward, the head of the FBI in New Jersey. “If (the Chinese) are able to acquire this research, they can save billions and quickly develop their own products to compete against the United States, be it in the world economic market or on the battlefield.”

Tunick had argued his client had not intentionally violated any rules and had downloaded information on his personal laptop to work on outside the office.

Tunick also said Liu had received only brief training on the company’s restrictions on sharing proprietary information and was unfamiliar with US import-export rules. He also sought to downplay the conferences in China as academic gatherings that featured professors from many countries, including the US.

Describing his client as “an educator”, Tunick said Liu’s punishment seemed harshly disproportionate to those levied against US corporations found guilty of violating the same trade laws.

“There was no financial motive, no quid pro quo,” Tunick said of Liu’s case. “On these types of alleged crimes, the Department of Justice treats corporations differently.”