Analysis of the performance of four-cascaded single-stage distributed amplifiers

In this paper, the analysis, design, and implementation of a hybrid broad-b and distributed amplifier based on four-cascaded single-stage distributed a mplifiers (4-CSSDAs) is demonstrated. The available gain produced by this a mplifier is significantly higher than conventional distributed amplifiers ( CDAs) using the same number of active devices. Simulation results for two v ersions of the 4-CSSDA are demonstrated, one with low interstage characteri stic impedance (Z(oint)) and the other with high Z(oint). Simulation result s show a number of advantages of the proposed amplifier over the CDA, in pa rticular, that the available gain can be increased by increasing the Z(oint ) Of the amplifier stages. Simulation predicts that gains approaching 50 dB could be achieved by appropriate design modification. Measured results for implementation of the two versions of the 4-CSSDA are reported. These show excellent performance with high gain, good gain flatness, input and output matching, flat group delays, and a low noise figure across a 1-10-GHz band width. The amplifier configuration achieved a measured wide-band performanc e (0.8-10.8 GHz) with up to 39+-/-2-dB flat gain using discrete packaged ac tive devices.