How was the effective electrical length calculated in this design?

hi guys,

referring to the attachment could anyone advice me how was the E_Eff (effective electrical length) was calculated. base on operating frequency and relative dielectric constant

Please take a look at Antenna theory by Balanis (second edition) page 728-729. You can find equations to calculate effective permittivity and extended length. from these values you can find the effective electric length for your line at your design frequency.

I didn't calculate depending on your given value. Please let me know if I'm wrong.

Correction: What I have found later, in this calculation extended length was not included. So the calculation is straight forward. For your case the effective permittivity is around 1.87. Therefore the wavelength is 149.9/sqrt(1.87) = 109.6 mm. Finally the effective electric length = (16050.5/109600)*360 = 52.72 degrees.