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Design Notes

MMIC DC Feed Line

This project illustrates how to build a DC feed line suitable for a MMIC design using Parameterized Subcircuits. 


In MMIC designs, a DC feed line with AC shunts to ground are often used with different sizes of capacitors. This projects demonstrates how one subcircuit containing a capacitor and a via to ground can be parameterized and used in hierarchy with different capacitor sizes.

Cap Schematic

In this schematic the Widths and Lengths of the capacitor and the microstrip line feeding to it are passed up using two of the "less" sign, and equation statements:

WCAP<<40, for example. These parameters are visible and changeable in hierarchy.

Cap_With_Feed Schematic

This schematic uses the parameterized subcircuit "Cap". Notice that the parameters values of each instance of the subcircuit can be changed individually.

AWR_MMIC Process Development Kit

The AWR_MMIC process development kit (PDK) was used in this example.  Expand the Libraries node in Circuit Elements and observe AWR_MESFET.  Here all of the elements of this library are available for use in your schematic.  Notice also that the LPF file AWR_MESFET.lpf has already been set up because a PDK was used.  This is an advantage of using a PDK in your design.

S_Parameters Graph

This graph shows the results of using one, two or three stages each consisting of a different value capacitance.

Schematic - 2_stage

Schematic - Cap

Schematic Layout - 3_stage

Graph - S_Parameters