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Cree Inc of Durham, NC, USA has released samples of what it claims are the first gallium nitride HEMT WiMAX products specified to operate at frequencies of up to 5.8GHz: the 15W CGH55015F and 30W CGH55030F GaN HEMT transistors covering the 4.9-5.8GHz frequency band.

Potential benefits include:

• a four-fold increase in efficiency compared with similar power-level GaAs MESFET devices;
• elevated frequency operation compared with commercially available silicon LDMOS;
• operational capability in the license-exempt 5.8GHz ISM (industrial, scientific and medical) band as well as 5.3GHz and 5.47GHz U-NII (Unlicensed National Information Infrastructure) bands; and
• linearity of better than 2.5% EVM (error vector magnitude) at average power under a WiMAX signal at 25% drain efficiency covering an instantaneous bandwidth of 5.5-5.8GHz.

Both transistors are available with ‘reference design’ amplifier platforms.

As business and residential customers continue to demand increased capacity and functionality for wireless networks, the transistors can enable efficient power amplifiers in small base-station formats (access points) for last-mile service using WiMAX-based architectures, says Cree. Such outdoor units can allow Internet service providers to maximize their return on investment (ROI) on spectrum due to the ability to offer tiered services (enabled by improved quality of service and wider channel bandwidths) to hundreds of broadband users from a single access point.

Cree developed the CGH55015F and CGH55030F GaN transistors to support the higher operational frequency and stringent efficiency and linearity requirements needed to enable next-generation WiMAX base-stations and access points, says Jim Milligan, director of RF and microwave products.

“These 5GHz transistors complement the CGH35060 product that we are also releasing now to round out our 3.5GHz GaN HEMT WiMAX product line,” he adds. “This 60W product is a direct result of customer feedback and offers customers greater flexibility for 3.5GHz WiMAX applications, particularly in Europe where remote radio heads (RRHs) are increasingly being used.”

See related items:

Cree samples new GaN HEMTs for WiMAX and launches AWR PDK for high-power GaN MMIC process

Cree samples GaN HEMTs that boost WiMAX PA efficiency by up to 50%

Search: Cree GaN GaN HEMT transistors WiMAX

See: Wide-bandgap RF devices: a $100m market by 2010

Visit: www.cree.com