Antenna Theory - FAQ's With Answers - 5.


This page contains basic questions and short notes on some of the keywords on antenna theory:


21) What is meant by cross field?

Normally the electric field E is perpendicular to the direction of wave propagation. In some situation the electric field E is parallel to the wave propagation that condition is called Cross field.


22) Define axial ratio?

The ratio of the major to the minor axes of the polarization ellipse is called the Axial Ratio (AR).


23) What is meant by Beam Area?

The beam area or beam solid angle or WA of an antenna is given by the normalized power pattern over a sphere.

WA = ò ò4p Pn ( q,f ) dW
Where dW = Sin q dq.df


24) What is duality of antenna?

It is defined as an antenna is a circuit device with a resistance and temperature on the one hand and the space device on the other with radiation patterns, beam angle, directivity gain and aperture.


25) State Poynting theorem?

It states that the vector product of electric field intensity vector E and the magnetic filed intensity vector H at any point is a measure of the rate of energy flow per unit area at that point. The direction of power flow is perpendicular to both the electric field and magnetic field components.

ALSO READ:

- Effective Aperture & Directivity Of A Short Dipole Antenna.

- What is Polarization & What Are It's Different Types?

- Define beam width of major lobe?

- List out the expression of beam width for broad side array and end fire array?

- What is meant by antenna beam width?

- Differentiate broad side and End fire array?

- What is the need for the Binomial array?

- Define power pattern?

- ...Return To Antenna Theory FAQ's Main Page.


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