How does meander type slot helps in miniaturization of the antenna ?

Hello everyone,
I am working on one project which is "Wide-band antenna for medical application" i am supposed to achieve the miniaturization of the same. Now i know the meander slot can help in miniaturization of antenna which i got to know by studying few papers but however i failed to find the theory of the same that how it is actually working and helps in miniaturization ? If anyone who can help me finding the theory of the same i would really appreciate the help.

Thank you.

first try to study about mender structure
it shifts frequency in fabricated prototype
further there should be 3 times larger gap between two conductor lines
but it compacts PCB by larger extent