Lumped elements

Updated September 21, 2011

This page serves as the main page for our discussion on capacitors, resistors and inductors.

Lumpy, the lumped element mascot

Click here to go to our lumped element filter page

Click here to check out a lumped element Wilkinson design

Click here to check out a lumped branchline coupler design

Click here to check out a bias tee design using lumped elements (new for October 2011!)

Click here for a discussion of how to calculate inductance and capacitance of transmission lines

What is a self-resonant frequency and how do you model it? It is all explained here (also new for October 2011!)

What is a lumped element? it is defined here at Microwaves101 as a passive device, that is reciprocal (these definitions are on our network theory page). But just as important, it must follow this rule of thumb!

To be considered a "lumped element", no feature of its structure can exceed 1/10 of a wavelength at the maximum frequency of its usage.

That being said, of the three primary lumped elements, resistors are the most well behaved as microwave elements, followed by capacitors, then inductors. It is possible to make lumped resistors and capacitors that work up to 100 GHz, but inductors usually stop being useful at X-band or lower.

Lumped elements don't always come in arbitrary values. Check out our page on RETMA values.

More to come!