Question

For the dominant mode propagating in a rectangular waveguide with breadth 10cm. the guide wavelength for a signal frequency 2.5 GHz will be equal to

• A. 20 cm
• B. 0.15 m
• C. 30 cm
• D. 0.12 cm

Answer 1

The correct option is B 0.15 m

Given dominant mode $\left(T{E}_{10}\right)$

$f=2.5GHz$

$a=10cm$

${\lambda }_c\left(T{E}_{10}\right)=2a=20cm$

$\lambda =\frac{c}{f}=\frac{3\times {10}^{10}}{2.5\times {10}^9}=12cm$

$\frac{1}{{\lambda }_g^2}=\frac{1}{{\lambda }^2}-\frac{1}{{\lambda }_c^2}$

$=\frac{1}{(12{)}^2}-\frac{1}{(20{)}^2}$

$\therefore {\lambda }_g=15cm$ (or) $0.15m$