Wideband distributed choke inductor for distributed power amplifiers

A method to design a wideband, low-loss, and highcurrent choke inductor suitable for use in a distributed power amplifier (DPA) is presented. The choke inductor is composed of several paralleled low-current inductors with small parasitics placed in a distributed manner. High-frequency gain-limiting parasitic shunt capacitors of these inductors are absorbed by the series inductors already present between the transistor drain terminals of the distributed amplifier. The measurement results of a 2-18-GHz DPA designed using a distributed choke inductor with an equivalent dc resistance of 0.32 Omega are given.