RF Electronics Chapter4: Transmission Line Transformers and Hybrids Page 100
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Canning [19] described how the inherent coupling between the outer connector of the
floating coaxial line Balun, can be represented by a transmission line with and impedance
of Zouter to ground. Figure 4.58 shows the corresponding coaxial line representation of
this Full-Marchand Balun.
Figure 4.59 Lite Marchand Balun.
The Marchand Balun can be simplified by connecting the centre conductor of Z
oc
to the
outer conductor of Z
oe
at the balanced line output and removing the centre conductor of
Zoe. Canning called that the 'Lite Marchand Balun' as shown in figure 4.59. This Lite
Marchand Balun is easier to realise in stripline or Microstrip technology.
Figure 4.60 Floating, Parallel and 2 Marchand Balun amplitude responses.
Figure 4.60 shows the magnitude and figure 4.61 shows the phase responses of these three
Baluns. For the Full and Lite Marchand Baluns, the output magnitudes at the coupled
ports S12 and S13 are exactly, the same and their phase difference is exactly 180. Both
these Marchand Baluns are thus ideal for producing the out of phase signals for driving
dipole antennae or balanced mixers.
RF Electronics: Design and Simulation
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