Reducing distortion caused by intermodulation in modern radar and communications systems has become a critical issue. One reason for this is that increasingly complicated digital modulation schemes are being used. Mixers are the main bottleneck when it comes to linearity in these systems, so highly linear mixers are essential.
The large voltage swing possible in gallium nitride (GaN) technology means that a fairly large local oscillator (LO) signal can be applied to the mixers. As a result, the conductance of these mixer devices alternates more or less instantaneously between two extreme states (on and off) in time with the LO signal. This leads to a maximum of mixer linearity.
- together with the Technical University of Denmark (DTU) on GaN-based mixer circuits for the X-band, which are highly interesting for various industrial applications. First experiments with FBH GaN transistors show excellent intermodulation properties when configured as resistive mixers.
- Development of fully integrated GaN mixer MMICs - a first single-balanced X-band mixer chip was fabricated on FBH's proprietary 0.25 µm GaN HEMT process.