Determine Reflection Coefficient & Load Impedance: Slotted Line 150ohms

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SUMMARY

The discussion focuses on determining the reflection coefficient and unknown load impedance (ZL) for a 150-ohm lossless transmission line. The voltage standing wave ratio (VSWR) is established at 3, with the first voltage maximum located 9 cm and the first voltage minimum at 3 cm from the load. The reflection coefficient is calculated using the formula VSWR = (1 + |Γ|) / (1 - |Γ|), leading to a conclusion that the load exhibits capacitive reactance due to the observed voltage minimum occurring first.

PREREQUISITES
  • Understanding of transmission line theory
  • Familiarity with voltage standing wave ratio (VSWR)
  • Knowledge of reflection coefficients and their calculations
  • Basic concepts of load impedance and reactance
NEXT STEPS
  • Study the derivation of the reflection coefficient from VSWR
  • Learn about the implications of capacitive and inductive reactance on load impedance
  • Explore transmission line equations in detail
  • Investigate the use of Smith charts for impedance matching
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Electrical engineers, RF engineers, and students studying transmission line theory who are interested in load impedance calculations and reflection coefficient analysis.

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A slotted line used on a 150ohm lossless transmission line connected to an unknown load impedance, ZL. The voltage standing wave ration is found to be equal to 3. The distance of the first voltage maximum from the load is found to be 9 cm, and the first voltage minimum is located at 3 cm from the load.Determine the followings:

i) The reflection coefficient of the load
ii) The unknown load impedance, ZL.

First thing first..
it's given dmax and dmin..
how am i going to translate it to smith chart..?
 
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You do not need to use a Smith chart for this. Just take a look at your standard set of transmission line equations.

VSWR = \frac{1+\left| \Gamma \right|}{1-\left| \Gamma \right|}

Now you can solve for the magnitude of the reflection coefficient. Next, use the location of the voltage minimum and maximum to derive the wave number and then the reflection coefficient.

Here's a sanity check for you. Since it reaches a minimum first away from the load then we can infer that the load has a capacitive reactance.
 

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