Improving the Gain-Frequency Performance of Cascaded Single-Stage Distributed Amplifiers with Bandpass Filter Structure

Abstract

In this paper a bandpass filter structure is proposed for realizing the artificial transmission lines of cascaded singlestage distributed amplifiers (CSSDA) and the basic analysis and design of the bandpass structured CSSDA (BP-CSSDA) is demonstrated. Some of the lower frequency region in the gain-frequency band of CSSDA is lost because of the bias components. Using the bandpass structure for realizing the artificial transmission lines, this lost frequency region can be added to the upper limit of the gain-frequency band. Therefore, BP-CSSDA gives more bandwidth than CSSDA using the lowpass structured lines. The gain can be increased by increasing the interstage termination impedance (Z 0int ) without decreasing the bandwidth. A graphical method for determining the maximum Z 0int is introduced in this paper. The simulation results given in this paper show the advantage of using the BP structured artificial lines in CSSDA.