Bandwidth improvement technique of distributed amplifiers using combined filtering structures

In this paper, we present a design technique of bandwidth improvement for distributed amplifiers (DAs), by using filtering structures. Both Chebyshev and Butterworth filters are used instead of the classical constant-k sections of the conventional DA in order to form respectively the gate and drain transmission lines of the new DA. To achieve this configuration, the filtering structures are designed using network synthesis method in order to improve the bandwidth performance. The complete designed circuit was implemented on 0.18 μm CMOS technology. The simulated results provide 12 ± 0.8 dB as a power gain, better than −12 dB input/output return loss, higher than +5 dBm as IIP3 and dissipates about 38.8 mW for a 1.8 V power supply. By applying the proposed design method, the new DA shows an improvement of 40% of the bandwidth compared to the conventional DA.