A linearity improved quad-band amplifier based on E-CRLH transmission line

This paper outlines a new class of quad-band amplifier (QBA) realized using extended composite right- and left-handed coupled lines. The design procedure to reach the QB CLs with predefined frequency operations and characteristic impedance of their ports is clearly presented. Designed and fabricated QBA operation frequencies are $f_{b_{1}} = 2.9\,GHz$ and ${\rm \;} f_{b_2} = 4.3\,GHz$ (output port B) ${\bi \;} \; f_{f_1} = 3.8\,GHz\; $ and $\; \; f_{f_2} = 5\,GHz\; $ (output port C) and the proposed structure exhibits a matching (−10 dB) bandwidth of over 300 MHz in each operation frequency bands. In addition, the insertion loss is smaller than 1 dB. The length and the width of the proposed QBA are approximately 7.7 and 2.4 cm, respectively. To further demonstrate the idea, a QBA is successfully designed and fabricated. The simulated and measured results of the proposed QBA are presented to verify the proposed idea.