Increase of

a

d

N

The case of synchronized region unbounded

d < 2 a π 2 N 2

λ 2 2 d

d > 2 a π 2 N 2

λ 2 4 a π 2 N 2

The case of the synchronized region bounded

d < 2 a π 2 N 2

R a ( 3 π + 2 ) + 2 π d 2 π d

d > 2 a π 2 N 2

R a N 2 ( 3 π + 2 ) + 2 π d N 2 4 a π 3