RF Electronics Chapter 2: Computer Simulation Page 16
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
behave different from inductors when their line length becomes comparable to a quarter
wavelength.
Figure 2.15. Final high-pass filter for diplexer.
Device Models
As RF devices become more complex, the circuit simulation software must also become
more complex in order to be able to accurately simulate these new RF devices.
Linear Models
Several different types of transistor models can be used. The simplest ones are linear
analytical models, such as the Hybrid, Pi or T models used in basic electronic design
subjects. Such models are used for teaching basic electronics at many Universities. For
these models, MWO treats the transistor as a linear device and only an AC analysis can
be performed. Figure 2.16 shows how a simple Hybrid Pi model can be realised in AWR.
Saving that schematic, as Hybrid Pi, allows that then to be imported in another schematic
by selecting Draw Add Subcircuit and then selecting Hybrid Pi and placing the
subcircuit in the new circuit diagram. Since this is a bipolar transistor model it is desirable
to change the Symbol by clicking on properties of the subcircuit and the selecting symbol
and then selecting BJT@system.syf as the symbol. In AWR DE, it is thus easy to produce
a model of an element and incorporate those elements in a circuit.
Figure 2.16. Hybrid Pi Transistor Model.
RF Electronics: Design and Simulation
16 www.cadence.com/go/awr
