Simple question about tuning return loss of antenna in practice by stick copper onto

Hi all
I am working with the base station antenna, I have a problem that the return loss does not reach -15 db. I need to tune the microstrips of phase shifter and power divider by stick pieces of copper onto the microstrip line. But I still don't have much experience.
If everyone has any material and experience, please share it with me

Thank you

What is your antenna type and frequency?
Copper piece length: from quarterwave down to ~1mm (by cutting)
width: may be the same as 50ohm line
You may move it along the line,solder,cut,move again. Each half wavelength along main line you probably obtain similar results, as impedance repeats. I've done some tuning this way, but it is not convenient. Simulation + manufacturing prototypes with stepped sizes based on simulated layout was much more productive.
Also you may try to change resistor in power divider, resistance +-20 Ohm of existing one.