=== Defining Lumped Circuits ===
[[File:PMOM64.png|thumb|Lumped Element dialog]]
To define a lumped RLC circuit in your planar structure, follow these steps:
* In the box labeled '''Offset''', enter the distance of the lumped element from the start point of the rectangle strip line or from the bottom of the via object, whichever the case. The value of '''Offset''' by default is initially set to the center of the line or via.
* In the '''Load Properties''' section, the series and shunt resistance values Rs and Rp are specified in Ohms, the series and shunt inductance values Ls and Lp are specified in nH (nanohenry), and the series and shunt capacitance values Cs and Cp are specified in pF (picofarad). Only the checked elements are taken into account in the total impedance calculation. By default, only the series resistor is checked with a value of 50S, and all other circuit elements are initially greyed out.<br />
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[[File:PMOM64.png]]
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Figure 1: The [[planar Module]]'s Lumped Element dialog.
EM.Cube's [[Planar Module]] allows you to define a voltage source in series with a series-parallel RLC combination and place them across the gap. This is called an active lumped element. If you choose the '''Active with Gap Source''' option of the '''Lumped Circuit Type''' section of the dialog, the right section of the dialog entitled '''Source Properties''' becomes enabled, where you can you can specify the '''Source Amplitude''' in Volts (or in Amperes in the case of PMC traces) and the '''Phase''' in degrees. Also, the box labeled '''Direction''' becomes relevant in this case which contains a gap source. Otherwise, a passive RLC circuit does not have polarity.
If the project workspace contains an array of rectangle strip objects or PEC via objects, the array object will also be listed as an eligible object for lumped element placement. A lumped element will then be placed on each element of the array. All the lumped elements will have identical direction, offset, resistance, inductance and capacitance values. If you define an active lumped element, you can prescribe certain amplitude and/or phase distribution to the gap sources just like in the case of gap and probe sources. The available amplitude distributions include '''Uniform''', '''Binomial'''''', Chebyshev''' and '''Data File'''.
'''Note that the impedance of the lumped circuit is calculated at the operating frequency of the project using the specified R, L and C values.''' As you change the frequency, the value of the impedance that is passed to the Planar MoM engine will change.
=== Calculating Scattering Parameters Using Prony's Method ===