Antenna Matching, Printed Folded Dipole Question

[blue_electron]

hi,

my design is to match a folded dipole to a chipcon-based differential RF ports (86.5+j43)

since the radiation resistance of a folded dipole is about 300 ohms, then i need to match this to a differential line of 86.5.

my question is:

is it possible for me to use a coplanar line designed with an odd-impedance(?) that matches the 300 ohm on one end and 86.5+j43 on the other end?

thanks!

 

[jian]

Hi, blue_electron:

If you try to match 300 ohms to 86.5 ohms, you can do it using a quarter wavelength 161 ohms TLN. However, if you want it to 86.5+j43, I think you do need to have 2 freedoms to do it. The solution is not unique. For example, you can use a quarter wavelength TLN plus some stub to achieve it. Regards.