A 6-12 GHz Push-Pull GaN Amplifier for Low Harmonic Drive Applications

This paper presents a fully integrated 6-12 GHz GaN MMIC push-pull amplifier for low harmonic drive applications. A folded Marchand balun is used to perform the unbalanced-balanced and balanced-unbalanced transformations. The three-stage push-pull amplifier provides in excess of 28 dB of small signal gain at a quiescent bias point of 25V, 200mA. The minimum saturated output power across the 6-12 GHz bandwidth is 32.3 dBm. The worst case second harmonic level under a saturated operating condition is -40 dBc, demonstrating the capability of the push-pull amplifier to suppress the even order harmonics, especially when the second harmonic is within the amplifier bandwidth.