This application note illustrates, through the design of a MMIC amplifier, common problems faced in designing, simulating, and producing the physical layout of an MMIC circuit, as well as validation steps needed to verify that the physical layout produces the desired result.
By Andy Howard
The amplifier design process depends on a number of factors, including desired specifications, availability of device models, designer preference, and more. This application note describes one of many potential sequences and applications that can be used to design a MMIC amplifier.
To begin, assume two stages of amplification will be required (See Figure 1). They are an output stage for power and an input stage to attain sufficient gain. The design is a balanced amplifier, consisting of two parallel, two-stage amplifiers, with branch-line couplers at the input and output implemented as lumped element equivalent circuits, to split the signal at the input and recombine it at the output after amplification (See Figure 2).
Due to the equations and graphs in this article a PDF version has been made available for you to download.