Skip to Main Content
In the presented DA (distributed amplifier) architecture, a feedback mechanism that aims at improving the gain with a minimum reduction in BW is proposed. It is seen that in the band where the distributed effect of the DA is in action, the ratio of the forward to reverse gain is substantial (and depends on the number of stages used). The input and output blocks are connected to this core stage to provide matching and stability This method is different from other techniques that improve gain (e.g., cascade of DAs or matrix amplifier) in that it uses a new internal feedback to fed signals go through one DA twice. The input, core and output DA blocks consist of 4/3/3 gain elements respectively except that the core DA uses series input capacitances at the gates for BW enhancement and biasing purposes. Terminations Zx and Zy are chosen to minimize undesired reflections. The input and output biases are fed through appropriate bias tees. The lower cutoff of the DA is set at 12 GHz for our application in a wideband mm-wave imaging module. This frequency could be extended to frequencies close to 1 GHz if appropriate AC-coupling capacitors are used.