Panasonic’s GaN Transistor Goes A Long Way
The high power transistor is suited to long-distance millimeter-wave communication and theoretically can be used for transmissions over 84km.
Panasonic has developed a high power Gallium Nitride (GaN) transistor for long-distance communication at millimeter-wave frequencies. A 25GHz wireless transceiver was fabricated using the GaN transistor. The device exhibits a maximum output power of 10.7W at 25GHz which theoretically enables communication over 84km.
The high power GaN transistor, fabricated on a silicon (Si) substrate is suited for mass production and takes advantages of the large diameter achievable with Si. The novel epitaxial structure on Si improves the crystal quality resulting in a high drain current of 1.1A/mm with a high carrier concentration.
A metal-insulator-semiconductor (MIS) gate structure with crystalline SiN film was used as a gate insulator, greatly increasing the gate breakdown voltage. Hence, a high drain voltage of 55V can be applied to the device.
The proprietary GaN device with a high current and high breakdown voltage enables high power operation of 10.7W at 25GHz. Panasonic say this is the highest power reported by GaN transistors on Si at this frequency. The firm also claims that the device exhibits the world highest power density of 2.4W/mm at 60GHz among reported GaN transistors.
The fabricated transceiver utilizes orthogonal frequency division multiplexing (OFDM) which is suited for high capacity data communication. The averaged output power of 2W out of the 10W from the GaN transistor can achieve 84km communication in theory.
The high power GaN transistor enables communication over far longer distances than those obtained using conventional GaAs transistors. Panasonic’s latest GaN transistor is very promising for future millimeter-wave long-distance communication systems with high speed and high data capacity.
So far, applications for 18 domestic and 3 overseas patents have been filed. This development is partially supported by "The research and development project for expansion of radio spectrum resources" of the Ministry of Internal Affairs and Communications, Japan.