  In this paper, we introduce a synthesis technique for transmission line based
decoupling networks, which find application in coupled systems such as
multiple-antenna systems and antenna arrays. Employing the generalized
$\pi$-network and the transmission line analysis technique, we reduce the
decoupling network design into simple matrix calculations. The synthesized
decoupling network is essentially a generalized $\pi$-network with transmission
lines at all branches. The advantage of this proposed decoupling network is
that it can be implemented using transmission lines, ensuring better control on
loss, performance consistency and higher power handling capability, when
compared with lumped components, and can be easily scaled for operation at
different frequencies.
