# Open circuit stub or short circuit stub? [closed]

What are the respective advantages of using either an open circuit stub or a short circuit stub?

• Well, given that they do different things, you would pick the one that does what you need. Seriously, this question is far too broad. You'll have to be a lot more specific about your application. – Dave Tweed Jan 12 '17 at 0:45

Consider a load with an impedance expressed as $z_L=A+jB$ and for simplicity, let's say the line characteristic impedance is $Z_o=50$. In order for you to match those two, you have to add something to the load so that the imaginary part gets cancelled out.
Adding a parallel stub and taking advantage of using admittance instead impedance to simplify the math, you can then find the admittance of the load, $y_L=C+jD$ and find a corresponding value for the admittance of the stub so that when you add $y_L$ and $y_{\text{stub}}$ you eliminate the imaginary part.
A short circuited stub has an admittance in the form: $y_{\text{short}} = -jX$ and an open stub has an admittance in the form: $y_{\text{open}} = -jY$. Then, if for example, the imaginary part of the load's admittance is positive, you want to use a shorted stub in parallel to cancel out the imaginary part.