Temperature correction in high frequency amplifier circuit

Generally GaAs amplifier used in high frequency amplifier circuits, tend to decrease gain as temperature rises. (The gain will decrease as temperature rises as shown on the figure by yellow line.) PXV1220S, thermal variable attenuator has a characteristic that attenuation will decrease as temperature rises. (The attenuation will decrease as temperature rises as shown on the figure by blue line.) It is possible to correct gain change generated by temperature change in an amplifier by connecting PXV1220S to an amplifier circuit in This makes it possible to obtain constant output without depending on the temperature. (The output will be constant as shown on the figure by purple line.) PXV1220S, thermal variable attenuator is passive element. Therefore it doesn’t need any control from outside. It is possible to correct temperature easily because it can sense temperature and change attenuation by itself.

Comparison with other styles

Another way can be thought of to control the output to be constant by feeding back the information monitoring the output power, but it will require more components, which reflects a higher price and a more complicated circuit. Also, it will generate a certain decrease even by this means, and there is not so big difference in the gain decrease when using PXV1220S. Moreover, when there are other things to be controlled at the same time, you can control them more easily by using PXV1220S because PXV1220S will remove factor of temperature. There are possibly other ways of controlling by using information programmed in advance. However, most of them will cost more and will be using a digital controlling method so it is impossible to have smooth continuous control with them.