GATE ECE
Electromagnetics
Transmission Lines
Previous Years Questions

## Marks 1

The voltage of an electromagnetic wave propagating in a coaxial cable with uniform characteristic impedance is $$V(l) = {e^{ - \gamma l\, + \,j\,\ome... A two wire transmission line terminates in a television set. The VSWR measured on the line is 5.8. The percentage of power that is reflected from the ... The propagation constant of a lossy transmission line is (2 + j5)$${m^{ - 1}}$$and its characteristic impedance is (50 + j0)$$\Omega $$at$$\omega...
A coaxial cable is made of two brass conductors. The spacing between the conductors is filled with Teflon $$\left( {{\varepsilon _r} = 2.1,\,\,\tan \,... In the following figure, the transmitter Tx sends a wideband modulated RF signal via a coaxial cable to the receiver Rx. The output impedance$${Z_T}$... To maximize power transfer, a lossless transmission line is to be matched to a resistive load impedance via a $$\lambda /4$$ transformer as shown. ... The return loss of a device is found to be 20 dB. The voltage standing wave ratio (VSWR) and magnitude of reflection coefficient are respectively. A coaxial cable with an inner diameter of 1 mm and outer diameter of 2.4 mm is filled with a dielectric of relative permittivity 10.89. Given $${\mu _... A transmission line of characteristic impedance 50$$\Omega $$is terminated by a 50$$\Omega $$load. When excited by a sinusoidal voltage source at ... A transmission line has a characteristic impedance of 50$$\Omega $$and a resistance of 0.1$$\Omega $$/m. If the line is distortionless, the attenua... If the scattering matrix [S] of a two port network is$$$\left[ S \right] = \left[ {\matrix{ {0.2\,\angle \,\,{0^ \circ }} & {0.9\,\,\angle \,\...
Many circles are drawn in a Smith chart used for transmission line calculations. The circles shown in Fig. represent ...
The VSWR can have any value between
In an impedance Smith chart, a clockwise movement along a constant resistance circle gives rise to
A transmission line is distortionless if
The magnitudes of the open-circuit and short-circuit input impedances of a transmission line are 100$$\Omega \,$$ and 25$$\Omega \,$$ respectively. Th...
Assuming perfect conductors of a transmission line, pure TEM propagation is NOT possible in
All transmission line sections shown in Fig. have characteristic impedance $${R_0}\, + \,j0$$. The input impedance $${Z_{in}}$$ equals ...
A transmission line of 50$$\Omega$$ characteristic impedance is terminated with a 100 $$\Omega$$ resistance. The minimum impedance measured on the l...
A lossless transmission line having 50 $$\Omega$$ characteristic impedance and lenght $$\lambda /4$$ is short ciruited at one end and connected to an...
The capacitance per unit length and the characteristic impedance of a lossless transmission line are C and $$Z_0$$ respectively. The velocity of a tra...
A load impedance (200 + j0) $$\Omega$$ is to be matched to a 50$$\Omega$$ lossless transmission line by using a quarter wave line transformer (QWT)....

## Marks 2

A microwave circuit consisting of lossless transmission lines $$T_1$$ and $$T_2$$ is shown in the figure. The plot shows the magnitude of the input re...
A lossless microstrip transmission line consists of a trace of width w. It is drawn over a practically infinite ground plane and is separated by a die...
Consider the 3 m long lossless air-filled transmission line shown in the figure. It has a characteristic impedance of $$120\pi \,\Omega$$, is termina...
A 200 m long transmission line having parameters shown in the figure is terminated into a load ܴ$$R_L$$. The line is connected to a 400 V source havin...
In the transmission line shown, the impedance $${Z_{in}}$$ (in ohms) between node A and the ground is ...
For a parallel plate transmission line, let v be the speed of propagation and Z be the characteristic impedance. Neglecting fringe effects, a redution...
A transmission line with a characteristic impedance of 100 $$\Omega$$ is used to match a 50 $$\Omega$$ section to a 200 $$\Omega$$ section. If the ...
A transmission line of characteristic impedance 50 $$\Omega$$ is terminated in a load impedance $$Z_L$$. The VSWR of the line is measured as 5 and t...
In the circuit shown, all the transmission line sections are lossless. The Voltage Standing Wave Ration (VSWR) on the 60W line is ...
A transmission line terminates in two branches, each of length $$\lambda /4$$, as shown.The branches are terminated by 50 $$\Omega$$ loads. The lines...
One end of loss-less transmission line having the characteristic impedance of 75 $$\Omega$$ and length of 1 cm is short-ciruited. At 3 GHz, the input...
A load of 50 $$\Omega$$ is connected in shunt in a 2-wire transmission line of $$Z_0$$ = 50 $$\Omega$$ as shown in the Fig. The 2-port scattering pa...
The parallel branches of a 2-wire transmission line are terminated in 100 $$\Omega$$ and 200 $$\Omega$$ resistors as shown in the Fig. The character...

## Marks 10

A 200 volt (r. m. s) generator having an internal resistance of 200 ohm is feeding a loss-less transmission line. The characteristic impedance and the...
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