Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How can we calculate the gain of an antenna?

Status
Not open for further replies.

mani_sohail

Junior Member level 1
Joined
Sep 1, 2005
Messages
18
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,389
Antenna Gain

How we calculate the gain of antenna?
high gain antenna is highy directional antenna?
the gain of Yaggi antenna is zero?
 

electronics_kumar

Advanced Member level 2
Joined
Nov 29, 2004
Messages
659
Helped
34
Reputation
68
Reaction score
9
Trophy points
1,298
Location
Tamilnadu
Activity points
5,552
Re: Antenna Gain

Antenna Gain= (Radiation resistance)/(loss resiatance+Radiation resistance)
loss resiatance calculated from eddy current loss,copperloss etc..
actually there exists many more formulas to fing Gain of a antenna...
2)high directional antenna will have maximum radiation intensity in particulat direction..that why it is called as high directional antenna
in terms of radiation intensity in particular direction with that of isotropic antennsalso,Gain can be calculated
 

albert22

Full Member level 6
Joined
Jul 20, 2004
Messages
333
Helped
68
Reputation
136
Reaction score
65
Trophy points
1,308
Activity points
5,005
Re: Antenna Gain

The gain of an antenna takes account of the antenna efficiency as well as its directivity. The formal definition of gain in any direction is "power density radiated in that direction divided by the power density which would have been radiated at that direction by a lossless (perfect) isotropic radiator having the same total accepted input power."
The gain is specified as a ratio (in Decibels) relative to a reference antenna. Being reference antennas the isotropic and the dipole.
If the gain is specified with the isotropic as a ref. it is expressed as dBi. If the ref. is a dipole you use dBd.
An isotropic antenna is a theoretical antenna with radiates equally in all directions. It is just a point in the free space.
For example a dipole antena has a gain of 2.2 dBi that is 1.6 times that of the ref.
The dipole is directive and the isotropic not, so you are achieving gain by concentrating the radiated energy in one direction.
A yagi rated at 7.2dBd will give you 2.15dB more gain than the one that is rated at 7.2dBi.
There are simulation programs that allow you to calculate gain and radiation pattern. Like those based on NEC as the EZNEC and MININEC. The data you should enter is the geometry of the antenna and the surrounding objets (if not on the free space).
Also there are programs to calculate yagi uda antennas.
The efficiency depends on its resistive losses in the antenna structure, and by resistive loss in objects which may lie near the antenna

Merry Christamas and Happy New year.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top