
684 Microwave Engineering
convenient option. It can also be used as a power combiner. If two signals
with equal phase and equal amplitude are fed to the two arms, there will
be no voltage across the isolation resistor and the combining process will
not result in any loss. In the case of non-identical inputs, a combining loss
may occur.
Line
Description Wire Structure Planar Structure
Lumped-Element
Approximation with
λ
/4 Impedance
Transformers Circuit
(a) A
short-
circuit stub
in parallel
with the
main line.
θ
θ
(b) An
open-
circuit stub
in parallel
with the
main line.
θ
θ
(c) A
short-
circuit line
coupled to
the main
line.
θ
θ
θ
(d) Coupled
short-
circuited