# Antenna array questions

Antenna arrays principles and properties are discussed using an interactive applet. Antenna arrays are formed by assembling identical in most cases radiating elements such as dipoles for example.

In the diagram below is shown an antenna array with its elements along the z axis such that the distance between each two successive elements is equal to d. Antenna arrays are characterized by their array factor which is given by the formula.

The main objective of the tutorial below is to explore how each of the parameters N, d and affect the radiating pattern of the array. On the left panel, you may use any of the sliders to change N the number of elements making the arrayd the distance between the elements and the phase. Note that the array is more directional. If you change to For these values of we have end-fire radiation. For this value of we have broadside radiation. Note that the direction of maximum radiation changes.

The maximum radiation can be oriented in any direction. This is the basic principle of electronic scanning using antenna arrays. Free Mathematics Tutorials. About the author Download E-mail. Antenna Arrays Antenna arrays principles and properties are discussed using an interactive applet. More on antennas antennas and parabolic reflectors. Privacy Policy. Search website.Planning for an excelling and compelling career as an Antenna Engineer? Visit Wisdom jobs to look into the various Antenna jobs available along with the training and assessment material for improving your knowledge base and sample resumes for a winning job and Antenna interview questions.

Visit our Antenna job interview questions and answers pag e designed by our experts and also those collected from individuals who already attended Antenna jobs, for both freshers and experienced so as to make yourself acquainted with the nature of the interview.

Answer : Antenna is a transition device or a transducer between a guided wave and a free space wave or vice-versa. Antenna is also said to be an impedance transforming device.

Question 2. Answer : Radiation pattern is the relative distribution of radiated power as a function of distance in space. It is a graph which shows the variation in actual field strength of the EM wave at all points which are at equal distance from the antenna. Question 3. Define Radiation Intensity? Answer : The power radiated from an antenna per unit solid angle is called the radiation intensity U watts per steradian or per square degree. The radiation intensity is independent of distance.

Question 4. Define Beam Efficiency? Question 5. Define Directivity? Answer : The directivity of an antenna is equal to the ratio of the maximum power density P q,f max to its average value over a sphere as observed in the far field of an antenna. Question 6. Answer : Effective aperture. Scattering aperture. Loss aperture. Collecting aperture. Physical aperture. Question 7. Define Different Types Of Aperture?

Answer : Effective aperture Ae : It is the area over which the power is extracted from the incident wave and delivered to the load is called effective aperture. Scattering aperture As : It is the ratio of the reradiated power to the power density of the incident wave.

### Multiple Choice Questions and Answers on Antenna & Wave Propagation

Loss aperture Ae : It is the area of the antenna which dissipates power as heat. Question 8. Define Aperture Efficiency? Answer : The ratio of the effective aperture to the physical aperture is the aperture efficiency. Question 9. Answer : The effective height h of an antenna is the parameter related to the aperture. It may be defined as the ratio of the induced voltage to the incident field.

Question What Are The Field Zones?SONAR b. Subsurface communication c. Radio navigation d. Phase b. Frequency c. Amplitude d. Wave equation. Sinusoidal b. Rectangular c. Square d. Solid bodies b. Ionized particles c. All of the above. Reflected b. Refracted c. Radiated d. D-region b. Normal E-region c. Sporadic E-region d. Appleton region. Electric field intensity b. Magnetic field intensity c. Current density d.An antenna, when individually can radiate an amount of energy, in a particular direction, resulting in better transmission, how it would be if few more elements are added it, to produce more efficient output.

It is exactly this idea, which led to the invention of Antenna arrays. An antenna array can be better understood by observing the following images. Observe how the antenna arrays are connected. An antenna array is a radiating system, which consists of individual radiators and elements.

Each of this radiator, while functioning has its own induction field. Therefore, the radiation pattern produced by them, would be the vector sum of the individual ones.

The following image shows another example of an antenna array. The spacing between the elements and the length of the elements according to the wavelength are also to be kept in mind while designing these antennas. The antennas radiate individually and while in array, the radiation of all the elements sum up, to form the radiation beam, which has high gain, high directivity and better performance, with minimum losses.

Antenna Theory - Antenna Arrays Advertisements. Previous Page. Next Page. Previous Page Print Page.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Antenna Arrays

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## Questions tagged [antenna-array]

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## Antenna Interview Questions & Answers

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