A short circuited stub is shunt connected to a T.L. as shown.

A short circuited stub is shunt connected to a T.L. as shown. If Z_o = 50 Ω, the admittance Y seen at the function of stub and the T.L. is—

1. (0.01 – j 0.02) mho
2. (0.02 – j 0.01) mho
3. (0.04 – j 0.02) mho
4. (0.01 – j 0) mho

When

l =	λ
	8

For short circuit stub

Z_in = Z₀		Z_L + j Z₀ tan βI
		Z₀ + j Z_L tan βI

= Z₀		0 + j 50 tan π/4
		Z₀ + j 0 tan π/4

=	Z₀[j 50]		∵ 2π/λ , λ/8 = π/4
	Z₀		Z_L = 0

= j 50
or

Y_in =	1	= - 0.02
	√50

when
I = λ/2 then βl = 2π/ λ · λ/2 = π

Z_in2 = Z₀		Z_L + j Z₀ tan π
		Z₀ + j Z_L tan π

= Z₀		Z_L + j Z₀ 0
		Z₀ + j Z_L 0

Z_L = 100
or
Y_in2 = 1/100 = 0.01
so resultant admittance Y = Y_in1 + Y_in2 = 0.01 – j 0.02 mho.