Double-Stub Matching
Editors : 盧韋伶、李銀順
Advisor : 江簡富 教授
To achieve impedance matching at 
, namely, 
. The admittance at 
is
The associated reflection coefficient is
The reflection coefficient at 
is
The associated admittance is
The admittance at 
is
Note that b1 does not appear in the real part. First compute b2 by solving the equation for the real parts.
The real part of 
can be computed
from 
and d1 to be 
,
The parameter b2 can be solved as
or
The parameter b1 can be solved from the equation for the imaginary
parts of 
as
where 
is the imaginary
part of , which is computed from
and d1.
In particular, the input impedance 
of a short-circuited line of length l is
The normalized input impedance of a
short-circuited line of length ls is 
, so that
Parameters used in the demonstration:
= 0.6 – j0.8, Z0 = 50 W, l1 = 0.13483λ, l2 = 0.32726λ, d12 = 0.375λ, d1 = 2λ