The change is not only driven by a desire for innovation, but also by necessity: With the discontinuation of the proven transistor family, for example the TIM series from Toshiba and the FLM series from Eudyna (later SEDI), a gap is emerging that developers worldwide must fill.
GaN-based semiconductors offer exactly what modern RF applications demand today: high power density, excellent efficiency and thermal robustness. Their material properties – high breakdown voltage, electron mobility and temperature resistance – enable operation at significantly higher voltages and frequencies than conventional technologies. This allows frequency ranges for GaN up to the Ka band and beyond, where classic GaAs or Si solutions reach their limits.
For developers, this radical change represents both an opportunity and a challenge: in addition to the advantages mentioned above, non-linearity and traps continue to occur, leading to a significant deviation from the usual amplification behaviour. Non-linearities must be taken into account even in the design of CW and pulse amplifiers. For data transmission linearization needs to be provided to reduce shoulder distances and in-band interference.
New generations of GaN MMICs on SiC substrates – such as those from Qorvo, Macom, Ampleon and UMS – now offer impressive performance values combined with improved efficiency and reliability. Kuhne, for example, uses RF-linearization to compensate for the additional non-linearities introduced by the use of GaN in amplifiers for video transmission in the C-band. In systems with access to baseband signal generation, on the other hand, it is possible to correct the non-linearities of the GaN output stage at the signal generation stage.
New semiconductor manufacturers, expansions of product ranges, mergers, announcements and cancellations of funding programs have shaped the semiconductor industry and, in particular, the GaN market in recent years. In the coming years, a stabilization of the market and product ranges will be necessary, so that developers can rely on reliable solutions in the long term.
