Dual-band Feedforward Linear Power Amplifier Using Equal Group Delay Signal Canceller

In this paper, the design of a novel dual-band feedforward linear power amplifier (FFW LPA) is presented. The frequencies of operation of the implemented dual-band FFW LPA are the digital cellular (f0=880 MHz) band, and the IMT- 2000 (f0=2.14 GHz) band, which are separated about 1.26 GHz. Using high power amplifiers (120 W PEP) for commercial base- station application, the IMD cancellation loop shows 20.45 dB and 25.04 dB suppression for the cellular and IMT-2000 bands, respectively, over a correction bandwidth of 100 MHz. From the adjacent channel leakage ratio (ACLR) measurement with CDMA IS-95A 4FA and WCDMA 4FA signal, we obtained 16.5 dB improvement at the average output power of 41.5 dBm for digital cellular band, and 18.6 dB improvement at the average output power of 40 dBm for IMT-2000 band under simultaneous operation.