Q21GATE 2005MCQ

Which one of the following does represent the electric field lines for the $TE_{02}$ mode in the cross-section of a hollow rectangular metallic waveguide ?

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📖 Explanation

Two maximas in the field along y-direction lndentifies $TE_{02}$

Q22GATE 2004MCQ

The phase velocity of an electromagnetic wave propagating in a hollow metallic rectangular waveguide in the $TE_{10}$ mode is

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Q23GATE 2003MCQ

A rectangular metal wave guide filled with a dielectric material of relative permittivity $\varepsilon _{r}$ = 4 has the inside dimensions 3.0 cm $\times$ 1.2 cm. The cut-off frequency for the dominant mode is

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📖 Explanation

\begin{aligned} v &=\frac{c}{\sqrt{\epsilon_{r}}}=\frac{3 \times 10^{8}}{2}=1.5 \times 10^{8} \\ f_{c} &=\frac{v}{\lambda_{c}}=\frac{1.5 \times 10^{8}}{6 \times 10^{-2}}=2.5 \mathrm{GHz} \\ \text { or, } f_{c} &=\frac{v}{2 a}=\frac{1.5 \times 10^{8}}{6 \times 10^{-2}}=2.5 \mathrm{GHz} \end{aligned}

Q24GATE 2002MCQ

The phase velocity for the TE10-mode in an air-filled rectangular waveguide is (c is the velocity of plane waves in free space)

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📖 Explanation

\begin{aligned} V_{p}&=\frac{c}{\cos \theta}=\frac{c}{\sqrt{1-\left(\frac{f_{c}}{f}\right)^{2}}} \\ \text { with } f&>f_{c^{\prime}} V_{p}>c \text { always. } \end{aligned}

Q25GATE 2001MCQ

The dominant mode in a rectangular waveguide is $TE_{10}$ , because this mode has

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Q26GATE 2001MCQ

The phase velocity of waves propagating in a hollow metal waveguide is

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📖 Explanation

\begin{aligned} V_{p}&=\frac{c}{\cos \theta}=\frac{c}{\sqrt{1-\left(\frac{f_{c}}{f}\right)^{2}}} \\ \text { with } f& \gt f_{c^{\prime}} V_{p} \gt c \text { always. } \end{aligned}