In this paper, a high-gain dual-band distributed amplifier (DBDA) based on the metamaterial transmission line (TL) is proposed. To have two separate frequency bands in the distributed amplifiers, the composite right/left-handed (CRLH) TLs are used instead of conventional TLs. Although both forward and reverse gains of the distributed amplifiers are available in this case, they suffer from their low gains. In this paper, to increase the DBDA power gain, a new circuit architecture for the CRLH TL is introduced. By using the proposed CRLH TL, a lower wave attenuation coefficient at the forward band of the DBDA is achieved than the conventional structures, which causes a higher forward power gain. Simulation results also show that the power gain of the proposed DBDA is about 28.5 dB at the desired frequency bands, and good agreement between the measurement and simulation results confirms the accuracy of the design method.
