coaxial line matching help

[beta3]

hi.
How can I calculate the length of patch for matching microstrip patch line of width 2mm with a characteristic impedance of 100 ohm,to a coaxial line with a characteristic impedance of 50 ohm?

 

[jiripolivka]

Please read some basics! The matching section is a quarter-wave long, with an impedance of SQRT[50 x 100] Ohms. You must indicate the wavelength or frequency of your signal, and for line impedance, you must know how to adjust line width as well how to use the line permittivity to adjust its impedance.

 

[beta3]

The problem is I am designing a microstrip antenna array,that if I want to match the line with other arrays,the problem goes to very hard! I want to matching with one line and other lines can be half-wavelength with open ends to not effecting in matching! I don't know this idea is good or not! Another problem is impedance that results in hfss,is varying with varying the length of coaxial cable! What should I do?!

 

[jiripolivka]

The problem is I am designing a microstrip antenna array,that if I want to match the line with other arrays,the problem goes to very hard! I want to matching with one line and other lines can be half-wavelength with open ends to not effecting in matching! I don't know this idea is good or not! Another problem is impedance that results in hfss,is varying with varying the length of coaxial cable! What should I do?!

I repeat that you need to read the basics! A half-wavelength open-end line behaves as a short, and this certainly will affect your matching. And by this you confirm no knowledge, so please read the basics!

 

[beta3]

I repeat that you need to read the basics! A half-wavelength open-end line behaves as a short, and this certainly will affect your matching. And by this you confirm no knowledge, so please read the basics!

I can't understand.with this equation: Zin=Z0 (Zl+jZ0 tanβl)/(Z0+jZl tanβl) and with open-end (Zl=∞),for l=λ/2,we have Zin=∞.this means short?????

 

[jiripolivka]

I can't understand.with this equation: Zin=Z0 (Zl+jZ0 tanβl)/(Z0+jZl tanβl) and with open-end (Zl=∞),for l=λ/2,we have Zin=∞.this means short?????

Have you heard about the Smith diagram? Impedances repeat after half wavelength!

 

[beta3]

Have you heard about the Smith diagram? Impedances repeat after half wavelength!

Yes,that's it! If,open-end repeats,what is the answer?!! short??!!