Redzone Wireless, the Camden-based company that pledged to extend high-speed Internet connections to 90 percent of Mainers by 2018, has doubled its initial footprint.

In a release issued Thursday, company President Jim McKenna said the wireless 4G LTE service has been extended to Westbrook, Camden, Rockland and Manchester-Augusta. It now is available to 100,000 homes, or 17 percent of Maine households.

The company kicked off its coverage in June by bringing service to Portland, Waterville and the Casco Bay islands.

“The incredibly rapid expansion of our network and service area demonstrates the viability of 4G LTE as a solution to Maine’s broadband challenge,” said McKenna in the release.

The company expects to extend coverage to more than 15 communities by the end of the year. Bangor is among the communities on deck, said Michael Forcillo, Redzone’s vice president of sales and marketing.

Redzone’s launch event on June 3 drew many of the state’s top officials, a reflection of the importance of getting high-speed Internet access to more parts of Maine. Attending were Gov. Paul LePage, who called Redzone’s arrival a “game changer,” University of Maine Chancellor James Page and George Gervais, commissioner of the Department of Economic and Community Development.

LePage and Page spoke of the importance of broadband to advance learning and commerce, and the impact that would have on elevating Maine from the bottom of national economic indicators. Maine has ranked close to the bottom on lists of broadband speeds by state, including a report based on Ookla NetMetrics data that said Maine ranks 49th out of the 50 states and a recent report from Akamai Technologies that puts Maine at 48th among U.S. states and far behind countries like Estonia and Macao.

Redzone is using bandwidth it secured earlier this year from the University of Maine System.

While hundreds of cellphones and other mobile devices use 4G LTE technology through the cellular networks, Redzone is the first company in the country to use 4G LTE to offer residential and commercial broadband service, according to Forcillo. McKenna estimated the cost to connect each Maine home with fiber-optic cable at $3 billion, and said wireless connections could be made for a 10th of that cost.

Forcillo said Thursday that the most popular plan the company offers is for $34 a month, which provides 15 megabits per second download speeds, 2Mbps upload speeds and unlimited data. He declined to say how many customers Redzone has signed up.