This paper proposes a novel design methodology for dual-band Doherty power amplifier (DPA) with simplified offset-lines. The methodology is validated with the design and fabrication of a 10 W GaN based DPA for Global System for Mobile Communications (GSM) and Wideband Code Division Multiple Access (WCDMA) applications at 0.90 GHz and 2.14 GHz, respectively. In the measurement results, the DPA achieves a drain efficiency (DE) of 51.2% with an output power of 37.2 dBm at the 6.5 dB output power back-off (OBO) from the saturated output power at 0.90 GHz, and a DE of 39.9% with an output power of 37.4 dBm at the 6.5 dB OBO at 2.14 GHz. Linearity results using 20 MHz 16QAM signal show an adjacent channel leakage ratio (ACLR) of -48 dBc and -43 dBc with the average output power of 37.2 dBm and 37 dBm at 0.90 GHz and 2.14 GHz, respectively.
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