The big carriers in wireless that have monopolized the best smartphones and dominate the cellular market will face a renewed threat from Raleigh upstart Republic Wireless beginning Thursday.

The privately held company, which launched its hybrid service based on a mix of cellular and Wi-Fi access in December, is unveiling its own “flagship” phone loaded with plenty of bells and whistles, says CEO David Morkin.

But perhaps even more importantly, the company also is unveiling new coverage plans that Morken calls “very disruptive.”

“Who can continue to pay $100 a month for service plans,” Morken asked rhetorically. Frustration with the high costs of wireless service drove Morken to develop Republic while he also was running Raleigh-based Bandwidth.com, a national provider of telecom and related services.

He declined to discuss specifics of the new plans.

“The combination of the right plan and the right phone makes this a strong offering,” Morken said.

The moves come after Republic got off to a very fast start but within a couple of months ran into resistance from people wanting a more advanced phone. After updating phones and plans, Republic still was not meeting sales and subscriber targets, Morken noted in an interview.

Asked if Republic had met its initial target of 50,000 subscribers within the first weeks of launch, Morken said “Yes.”

However, he noted than since then growth has been “short of projections.” He would not discuss the current subscriber total.

Republic received extensive publicity from a wide range of media outlets about its service, especially for the unlimited plan of less than $20. The company’s initial phones were made by Motorola and included ability to directly connect to Wi-Fi access when available or to Sprint’s cellular network.

Morkin disclosed Republic’s phone launch during a panel discussion at the Council for Entrepreneurial Development’s annual “Tech Venture” conference Wednesday in Raleigh. He then declined to talk about specifics – the manufacturer of the phone and its features or prices.