Exam 1: Antennas and Frequency Multipliers

In a diode frequency multiplier, an input signal of frequency fo applied to the diode is terminated with__________at all frequencies other than required harmonic.

Gain of an antenna is always greater than the directivity of the antenna.

An antenna has a field pattern E (?) =cos ?. cos 2?. The first null beam width of the antenna is:

The basic equation of radiation that is applied to any antenna irrespective of the type of the antenna is:

The major drawback of frequency multipliers is that they have:

Oscillators operating at millimeter wavelength are difficult to realize and are also less efficient.

__________of an antenna is a plot of the magnitude of the far field strength versus position around the antenna.

If the beam width of an antenna in two orthogonal planes are 300 and 600. Then the directivity of the antenna is:

Resistive multipliers are more efficient as compared to reactive multipliers.

The number of patterns radiation pattern required to specify the characteristic are :

Dipole antennas are an example for:

Reactive multipliers have a disadvantage that they cannot be used at very high frequencies and they become less efficient.

For a resistive frequency multiplier of multiplication factor 2, the maximum theoretical conversion efficiency is:

If the power input to an antenna is 100 mW and if the radiated power is measured to be 90 mW, then the efficiency of the antenna is:

A major disadvantage of frequency multipliers is that they multiply the noise factor along with frequency.

A parabolic reflector used for reception with the direct broadcast system is 18 inches in diameter and operates at 12.4 GHz. The far-field distance for this antenna is:

__________antennas consist of a regular arrangement of antenna elements with a feed network

The beam width of the antenna pattern measured at half power points is called:

If an antenna has a directivity of 16 and radiation efficiency of 0.9, then the gain of the antenna is:

__________is a device that converts electrons to photons or vice-versa.