Pages

Search This Blog

Friday, March 18, 2011

Impedance Taper Selection Guide

As mentioned earlier, Tapered microstrip baluns can be classified according to the type of taper used. Four widely used tapers are:

  • Linear
  • Exponential (E)
  • Triangular (T)
  • Klopfenstein (K)
The selection of taper can have multiple criteria but the general important considerations are the simplicity of the design and the production of a smooth transition of impedance from one end to other. The size of the impedance section is also a critical factor in certain design situations where length of the section can not exceed a given limit. Linear taper is the simplest of all the tapers and can be designed quickly, however, the trade-off is in the length of the taper. Similar is the case with the triangular and exponential taper, however, but as there designs are a little complex from the the linear taper, they provide a better response in impedance transformations (the reflection coefficient are lower than that of linear taper along the lenght).

The klopfenstein taper is defined by a very complicated equation, however, the advantage of this taper is that the reflection coefficient is minimum over the passband. Alternatively, the Klopfenstein taper provides the minimum taper length for a maximum reflection coefficient specification.

Recommended Readings:
[2] David Pozar, "Microwave Engineering"

No comments:

Post a Comment