The quarter-wavelength in filter

I have a problem with quarter wavelength

How can I realize that which line in passive filter is quarter wavelength?

for example, microstrip line that is connected to varactor is the quarter wavelength?

This online microstrip calculator can tell you the microstrip line electrical length function of dielectric Er, W, H, and length.
Quarter wavelength means 90 degrees.

http://www.emtalk.com/mscalc.php

thanks for replying

I have other problem with calculating of L. In some papers, the physical length of microstrip is based of Lamda (for example L=25mm so L=0.07Lamda, e=3)