High linearity over a broad frequency band is a requirement in many RF amplifier designs. This paper shows that adding low impedance terminations at the envelope frequency (�2-�1) to the input of a Gallium Arsenide (GaAs) Heterojunction Bipolar Transistor (HBT) Distributed Amplifier (DA) improves the third order output intercept point (OIP3) over a bandwidth of 0.5 GHz to 3 GHz by up to 7.4 dB. Furthermore, OIP3 can be increased up to 19.2 dB above P1dB. Results show that the improvement in OIP3 comes without lowering gain, return loss or P1dB. Simulation and measurement results also show that the optimum termination is a short circuit with a small capacitive reactance at the envelope frequency. By varying the frequency spacing (��) from 1 MHz to 50 MHz, the resulting variation in OIP3 after the addition of the traps is less than 7. © 2010 EuMA.