GATE EC Transmission Lines questions

Consider a $300 \; \Omega$, quarter-wave long (at $1 \; \mathrm{GHz}$ ) transmission line as shown in the figure. It is connected to a $10 \mathrm{~V}, 50 \; \Omega$ source at one end and is left open circuited at the other end. The magnitude of the voltage at the open circuit end of the line is

A lossless transmission line is terminated in a load which reflects a part of the incident power. The measured VSWR is $2.$ The percentage of the power that is reflected back is

A short-circuited stub is shunt connected to a transmission line as shown in the figure is. If $Z_{0}=50 \mathrm{ohm}$, the admittance $Y$ seen at the junction of the stub and the transmission line is

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

Two identical antennas are placed in the $\theta=\pi / 2$ plane as shown in the figure. The elements have equal amplitude excitation with $180^{\circ}$ polarity difference, operating at wavelength $\lambda$. The correct value of the magnitude of the far-zone resultant electric field strength normalized with that of a single element, both computed for …

The phase velocity for the $\mathrm{TE}_{10}$ – mode in an air-filled rectangular waveguide is ( $c$ is the velocity of plane waves in free space)

In an impedance Smith chart, a clockwise movement along a constant resistance circle gives rise to

The $\text{VSWR}$ can have any value between

The dominant mode in a rectangular waveguide is $\text{TE10,}$ because this mode has

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

A transmission line is distortionless if

In a uniform linear array, four isotropic radiating elements are spaced $\frac{\lambda}{4}$ apart. The progressive phase shift between the elements required for forming the main beam at $60^{\circ}$ off the end-fire is

A medium wave radio transmitter operating at a wavelength of $492 \mathrm{~m}$ has a tower antenna of height $124 \mathrm{~m}$. What is the radiation resistance of the antenna?

If the diameter of a $\frac{\lambda}{2}$ dipole antenna is increased $\operatorname{from} \frac{\lambda}{100}$ to $\frac{\lambda}{50}$, then its

The magnitudes of the open-circuit and short-circuit input impedance of a transmission line are $100 \; \Omega$ and $25 \; \Omega$ respectively. The characteristic impedance of the line is,

Two coaxial cables $1$ and $2$ are filled with different dielectric constants $\varepsilon_{r 1}$ and $\varepsilon_{r 2}$ respectively. The ratio of the wavelengths in the two cables, $\left(\lambda_{1} / \lambda_{2}\right)$ is

A rectangular waveguide has dimensions $1 \mathrm{~cm} \times 0.5 \mathrm{~cm}$. Its cut-off frequency is

A rectangular waveguide has dimensions $1 \mathrm{~cm} \times 0.5 \mathrm{~cm}$. Its cut-off frequency is

For an $8$ feet $(2.4 \mathrm{~m})$ parabolic dish antenna operating at $4 \; \mathrm{GHz}$, the minimum distance required for far field measurement is closest to

Indicate which one of the following will $\text{NOT}$ exist in a rectangular resonant cavity.