Linearizers for ${Q}$ - and ${V}$ -Band TWTAs

The need for information transmission at ever increasing data rates is moving satellites to the millimeter-wave (MMW) bands. The efficient transmission of information requires linear systems. For satellites transmission linear, high-power amplifiers (HPAs) are essential in both orbit and on the ground. This paper describes linearizers that have been developed for the use with TWTAs at Q (43.5–45.5 GHz) and the new V (47–52 GHz) satellite bands. This paper will also discuss linearizer work for even higher bands that will be needed in the near future. Today’s TWTA linearizers can provide all the frontend functions needed by an HPA including upconversion, gain, commandable attenuation, commandable predistortion, and the RF power for direct drive. The use of linearization at MMW is discussed and measured characteristics of the linearizers such as power transfer and carrier to intermodulation (IM) ratio (C/I) shared. Linearized MMW TWTAs are shown to achieve an AM/PM of 30 dB with an error vector magnitude of <2%.