Because in single stub method stub position has to be adjustible which create error......this is notin the case of double stub position method.........
It requires stub should be placed in a definite point on line, it requires two adjustments both the location and the direction of the stub
short circuited stub matching network is a s/c length of transmission line is added in parallel to the main line (physically perpendicular) at the precise location so that its reflected wave exactly cancels out the reflected wave from the load. then all the power is delivered to the load. (since it can not be absorbed by the purely reactive matching network) it thus provides a "perfect Match' at the design frequency and results in more efficient use of the power.
STUB-IN STUB-IN STUB-IN
Stub Wiberg died in 1929.
Stub Wiberg was born in 1875.
Jens Stub died in 1819.
Jens Stub was born in 1764.
Sverre Stub was born in 1946.
Stub Barron was born in 1890.
Stub Barron died in 1979.
Ambrosius Stub was born in 1705.