Q. In a uniform linear array, four isotropic radiating elements are spaced λ/4 apart. The progressive phase shift between the elements required for forming the main beam at 60° off the end fire is

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Q. After reflection from a plane conducting surface, the apparent velocity of electromagnetic wave becomes greater than the velocity of light in free space is called

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Q. In a turnstile antenna the crossed dipoles are excited with voltages

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Q. Directivity of antenna is defined as

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Q. Consider the following; for a loss-less transmission line we can write,

1. Zin = - jz0 for a shorted line with l = λ/8
2. Zin = ± j ∞ for a shorted line with l = λ/4
3. Zin= jz0 for an open line with l = λ/2
4. Zin = 0 for a matched line of any length

Select the correct answer using the codes given below codes.

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Q. Strip lines are used at

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Q. ∇² is

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Q. End fire array has narrow bandwidth.

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Q. Which of the following antenna is best guided by a waveguide?

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Q. Poynting vector is the rate of energy flow having

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Q. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of

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Q. If a wave is propagated in free space, it will be in nature of

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Q. When the height of a vertical earthed antenna is less than λ/4

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Q. Which of the following is a circularly polarized antenna?

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Q. During day time ionosphere consist of

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Q. To couple a coaxial line to a parallel wire line, it is best to use a

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Q. Which of the following is λ/2 length?

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Q. Which of the following is the main difference between waveguide and transmission line?

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Q. Television signals are propagated as ground waves.

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Q. The characteristic impedance of loss less transmission line is

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