Problem Solving on Wave Propagation and Antenna.pptx

8/13/2019 Problem Solving on Wave Propagation and Antenna.pptx

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Problem Solving on Wave

Propagation and Antenna


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Problem 1

One hundred watts power output wasderived from the final stage amplifierof a transmitter of a station which is10 km away from a receiving station. Thepower output was fed to a transmissionline with attenuation of 0.5 dB/m.Assume that the antenna used has a gainof 2.15 dB, has a height of 100 m and ismatched with the transmission line used,calculate:a) the electric field strengthb) the magnetic field strengthc) the amount of power incident on a receiving

aerial with an effective area of 5 m 2 d) What will be the values of E rms and H rms at a

distance of 100 km?


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Problem 2

Medium 1 is made of silicon and medium 2is made of glass. Their relativepermittivity are 11.83 and 3.66respectively. For an angle of refractionof 60 degrees, determine:a) the index of refraction of medium 1

b) the velocity factor of medium 2

c) the incidence angle

d) the angle of reflection


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Problem 3

Considering ground-wave propagation,what will be the induced voltage on areceiver antenna with a height of / 4(operating frequency of 2 MHz) if a

125 m transmitting antenna (operatingat the same frequency) has an rmscurrent of 8 A. Assume that thedistance between the two antenna is20 km.


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Problem 4

A radio communication link is to beestablished via the ionosphere. The maximumvirtual height of the layer is 110 km. atthe midpoint of the path and the maximumvalue of electron density of the ionosphereis 1.8 x 10 6 per cm 3 . If the skip distancebetween the radio stations is 500 km, usingflat terrain analysis, determine:a) the angle of radiation

b) the angle of incidencec) the critical frequency

d) the MUF

e) the OWF


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Problem 5

Considering space-wave propagation,the transmitting station transmits100 W of power at frequency of 80 MHzusing half-wave dipole antenna 20

meters above the ground. If thereceiver antenna is also a half-wavedipole with a height of 4 m,determine:a) the radio horizonb) the optical horizon

c) the field strength at the receiving antenna if itspath distance is equal to the radio horizon


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Problem 6

An antenna operating at a frequency of30 MHz has a radiation resistance of72 ohms and loss resistance of 8 ohms.If the power coming from thetransmitter connected to this antennaby a lossless transmission line is 100W, and the antennas directive gain is20, calculate:a) the antenna lengthb) the antenna length considering end effectc) the antenna efficiencyd) the dissipated powere) the radiated powerf) the antenna gain in dBi and dBdg) the EIRP in dBm


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Problem 7

An antenna system, consisting of atransmitting half-wave dipoleantenna that has an input power of10 W and an elementary doublet onthe receiving end which is 40 kmaway. Determine:a) the power density of the transmitting antenna

b) the capture area of the receiving antenna ifthe operating frequency is 30 MHz

c) the captured power of the receiving antenna


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Problem 8

Consider the following specifications ofdifferent antennas:

If all are operating at 10 GHz, which antenna isbest in terms of:

a. gain

b. beamwidth

Parabolic antennaDiameter 8 mEfficiency: 60%

Horn AntennaE-plane aperture: 60 mmH-plane aperture: 80 mm

Helical antennaNo. of turns 8Diameter: OptimumPitch: Optimum


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END OF SESSION

ENGR. TIMOTHY M. AMADOInstructor, Technological University of the Philippines Manila

[email protected]/0932-3581976

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Problem Solving on Wave Propagation and Antenna.pptx