Final answer:
To design a double-stub tuner with lambda/8 spacing to match a load admittance, calculate the reflection coefficient, stub impedance, and stub length.
Step-by-step explanation:
To design a double-stub tuner using open-circuited stubs with a lambda/8 spacing, we need to match the load admittance YL =(0.4+j1.2)Y0.
First, we need to calculate the reflection coefficient of the load, which is the ratio of the reflected voltage to the incident voltage at the load. The reflection coefficient is given by:
ΓL = (YL - Y0)/(YL + Y0)
Next, we need to find the stub impedance necessary to match the load. The stub impedance is given by:
Zs = Z0(1 + ΓL)/(1 - ΓL)
Finally, we need to calculate the stub length necessary to provide a lambda/8 spacing. The stub length is given by:
Ls = λ/8
By calculating the reflection coefficient, stub impedance, and stub length, you can design a double-stub tuner to match the given load admittance.