A Quad-Band Distributed Amplifier With E-CRLH Transmission Line

A quad-band microstrip distributed amplifier (DA) based on the extended composite right-and left-handed (E-CRLH) transmission lines (TLs) technique is presented. The design procedure to realize the quad-band E-CRLH TLs at four arbitrary frequencies is presented. The quad-band operation is achieved for a DA using three cells, which each consists of a transistor, microstrip line, and E-CRLH. This DA operates in four frequency bands: two bands in the backward direction and two bands in the forward direction. Moreover, the analytical and experimental results show that the proposed quad-band DA exhibits 10-dB gain in the operational bands. In addition, at these frequency bands, the return loss is greater than 10 dB. The excellent agreement between the simulation and measurement results confirms the accuracy and efficiency of the design technique for the proposed structure.