Larger antenna size means better reception?

[tyne]

Antenna size

Is it true that the larger the size of the antenna, the better reception it will have?

If its true, based on what principles and formula demostrates that?

Thanks :?:

 

[jian]

Re: Antenna size

Hi, tyne:

It is not necessary. The feed point is very critical. If you do not design the feed very well, you will not get good resonance and you will not receive strong signal.

Regards.

 

[IanP]

Re: Antenna size

Of coures transmitted or received power depends on the size of an atenna ..
For example:

How does an antenna size affect my CB radio?

If you put 4 watts into a four-foot antenna, you will get the same power out of that antenna as if you were putting 2 watts into a 102-inch whip.
If you put 4 watts into a 3-foot antenna you will get the same power out as if you wre putting about 1.5 watts into a 102-inch whip.
If you put 4 watts into a 7.5 inch antenna on a hand held CB, it would put out as much power as a third of a watt into a 102-whip.

However, it is to complex story with formulas which will be able to predict the exact amount of energy received (or transmitted) by antennas of different sizes in similar conditions ..
More considerations on antena sizes can be found in this publication:
**broken link removed**
(in particular compare sections on the full-size whip (¼ wavelength) and so called "short whip") ..

Regards,
IanP

 

[tomcat_x]

Re: Antenna size

The situation like this is often in small antennas ,

The resonance structure is related to the wave length.

for example , in 2.4GHz ,

the PIFA has 3cm length , but the longer length has no bonus for its performance.