ANTENNA AND MICROWAVE ENGINEERING- REVISION QUIZ

2.

An antenna that just serves as a reference and is hypothetical is the ________ antenna

Explanation
The correct answer is "isotropic". An isotropic antenna is a hypothetical antenna that radiates power uniformly in all directions. It is used as a reference to compare the performance of other antennas. The term "isotropic" refers to the equal radiation in all directions, regardless of the polarization or frequency.

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3.

The region of the field of the antenna where the angular field distribution is independant of the distance is

Reactive near field
Far field
Radiative near field
Fresnel region

Correct Answer

A. Far field

Explanation

The far field is the region of the field of the antenna where the angular field distribution is independent of the distance. In this region, the radiated electromagnetic waves have spread out enough to form a nearly spherical wavefront. The far field is characterized by a constant angular field distribution, meaning that the pattern of the radiated electromagnetic waves remains the same regardless of the distance from the antenna. This region is important for long-range communication and is commonly used for applications such as radio broadcasting and satellite communication.

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4.

Directivity, Gain and Aperture are directly related...true or false?

True
False

Correct Answer

A. True

Explanation

Directivity, gain, and aperture are directly related because they all refer to the ability of an antenna or sensor to focus and concentrate its radiation or reception in a specific direction. Directivity is a measure of how well an antenna can transmit or receive signals in a particular direction, while gain is a measure of the increase in signal strength achieved by an antenna compared to a reference antenna. Aperture, on the other hand, refers to the effective size of the antenna or sensor, which affects its directivity and gain. Therefore, all three concepts are interconnected and directly influence each other.

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5.

The radiation resistance of a half wave dipole is

74 ohms
75 ohms
73 ohms
50 ohms

Correct Answer

A. 73 ohms

Explanation

A half wave dipole antenna is a resonant antenna that is commonly used in radio communication. The radiation resistance refers to the resistance that is associated with the conversion of electrical energy into electromagnetic radiation. In the case of a half wave dipole, the radiation resistance is typically around 73 ohms. This value is a result of the antenna's physical dimensions and the wavelength of the transmitted signal. The radiation resistance plays a crucial role in determining the efficiency and performance of the antenna.

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6.

To find the field components of an antenna, the analysis should be started from the ----- of the radiation

Point
Vector potential
Scalar potential
Fields

Correct Answer

A. Point

Explanation

To find the field components of an antenna, the analysis should be started from the point of the radiation. This means that the analysis should begin at the specific location where the radiation is originating from. By starting from this point, it allows for a more accurate and focused analysis of the antenna's field components, enabling a better understanding of its behavior and performance.

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7.

The helical antenna is the hybrid of

Dipole and loop antenna
Spiral and dipole antenna
Two half wave dipoles in the form of helix
Spiral and loop antenna

Correct Answer

A. Dipole and loop antenna

Explanation

The helical antenna is a hybrid of a dipole and loop antenna. It consists of two half wave dipoles in the form of a helix. The helical shape of the antenna allows it to have a wider bandwidth and higher gain compared to a simple dipole or loop antenna. The combination of the dipole and loop elements in the helical antenna helps to achieve a more compact design while maintaining good performance characteristics.

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8.

Which of the following feed techniques in the reflector antenna, avoids blockage

Front
Offset
Cassegrain
Offset cassegrain

Correct Answer(s)

A. Offset
A. Offset cassegrain

Explanation

The offset and offset Cassegrain feed techniques in a reflector antenna are designed to avoid blockage. In these techniques, the feed is positioned to the side of the main reflector, allowing the incoming and outgoing signals to pass unobstructed. This arrangement helps to minimize any blockage caused by the feed itself, resulting in improved antenna performance.

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Antenna And Microwave Engineering- Revision Quiz

The solid angle is measured in

Quiz Preview

An antenna that just serves as a reference and is hypothetical is the ________ antenna

The region of the field of the antenna where the angular field distribution is independant of the distance is

Directivity, Gain and Aperture are directly related...true or false?

The radiation resistance of a half wave dipole is

To find the field components of an antenna, the analysis should be started from the ----- of the radiation

The helical antenna is the hybrid of

Which of the following feed techniques in the reflector antenna, avoids blockage