Stealth mode wireless chip maker Quantenna Communications on Tuesday said it got $12.7 million in a second round of funding and plans to use the investment to test its chips in real-world customer environments.

The Sunnyvale, California-based chipset maker offered scant details on exactly what wireless markets it plans to focus on, but Wi-Fi, WiMAX, and a slew of so-called fourth-generation wireless services seem the most likely targets.

But Quantenna will have to move fast. That's because there's a heap of other startups and large incumbents already camped out in those areas, according to iSuppli analyst Francis Sideco,

Quantenna has focused its development efforts on multiple-input and multiple-output (MIMO )technology--a system that uses multiple antennas at both ends of a wireless communications session to improve both the bandwidth and range of communications.

"MIMO technology has been power-hungry and big, and that has made it unattractive in the market so we are solving those problems," Quantenna CEO Behrooz Rezvani said.

MIMO has emerged as a key technology in products that support the Wi-Fi standard known as 802.11n and also plays a major role in products for WiMAX, a long range wireless communication technology that is still in its commercial infancy.

Quantenna, which plans its official launch in the first half of 2008, is developing chips that, it said, can shrink both the size and excessive power consumption of MIMO handsets, base stations, and access points.

Quantenna's latest cash infusion, which was led by Sigma Partners and included Grazia Equity, and previous investors Sequoia Capital and Venrock Associates, raises the startup's funding total to $25 million.