Dear Meenakshi Kohli ,

You got a number of good answers and I want to make somethings more clear.

The antenna has certain specific resistance which is the radiation resistance Rr and has also some loss resistance Rl

So the input power P= I^2 Rt , Rt=Rr+Rl

I is the effective value of the current.

So, as a rating of the antenna one must construct it to withstand the maximum current in the antenna conductors. This is due to thermal fusing effects of the wires.

The other rating is the maximum voltage that can be applied on the antenna

where P= V^2/Rt

So the antenna must be constructed to withstand the maximum voltage defined by the maximum power the relation given above. The maximum voltage is limited by the breakdown of the gap between the two poles of the antenna as these two points are the nearest from each other.

These simple analysis may answer your question in a simple manner.

Best wishes

Hello Meenakshi Kohli ,

If your antenna starts producing a corona discharge in the surrounding air, then you are trying to force too much power through it. The easiest way to check for a corona discharge is in the dark with your eyes dark adapted. For safety, use a telescope on a tripod (or a long focus microscope on a stand, sometimes referred to as a cathetometer) so you are not too near the antenna.

Regards,

Tom Cuff

Thomas' answer hits half of the problem (and the most common) which is voltage breakdown of the dielectric (usually air), although it depends somewhat on the antenna design if that would dominate. A loop antenna, for example, probably won't have a corona. The other is physical heating due to resistive losses in the antenna and feed cables. Mismatch plays a large part in the latter since the cable and supply amplifier may need to handle a lot more power than you're actually radiating. If something melts, that's bad, just as if something arcs. Note that another way of looking at these two mechanisms is that one is voltage related, the other is current related.

hank you everyone for your reply. so, how should I guess may be, this much power this antenna can handle and not discharge corona? When I design, antenna, i usually look for impedance matching, S11 and radiation plots and gain vs freq.

How can I calculate power this antenna can handle?

Selecting antenna/power amplifier combinations

https://www.ahsystems.com/articles/antennas-and-amplifiers.php

Meenakshi Kohli Total 'accepted power' at antenna port goes as loss and radiation. If resistive losses are high, then thermal factor may dictate the limit. Too much radiated power leads to high intensity electric fields (and may cause corona).

Calculation of resistive loss may be computed for simple/ regular antenna structures but may need measurement techniques for other types. Recollect that current is not constant across the antenna elements! Radiation limits may be governed by regulation on intensity limits for health/ safety/ interference reasons. You may want to check for such based on band/ application/ other criteria.

The power handling is depend upon following factors

1) The gap between live power point and nearest ground

2) The breaking power capacity of insulator between feed centre and ground

3) Current handling capacity of antenna element where current is from I^2*R

The least capacity (weak link) will decide the handling capacity

Hope this clarify

Dear Meenakshi:

you can use a Path Loss Calculator like this at URL: https://www.rac.ca/tca/Received%20Signals.html

Dear Meenakshi Kohli ,

You got a number of good answers and I want to make somethings more clear.

The antenna has certain specific resistance which is the radiation resistance Rr and has also some loss resistance Rl

So the input power P= I^2 Rt , Rt=Rr+Rl

I is the effective value of the current.

So, as a rating of the antenna one must construct it to withstand the maximum current in the antenna conductors. This is due to thermal fusing effects of the wires.

The other rating is the maximum voltage that can be applied on the antenna

where P= V^2/Rt

So the antenna must be constructed to withstand the maximum voltage defined by the maximum power the relation given above. The maximum voltage is limited by the breakdown of the gap between the two poles of the antenna as these two points are the nearest from each other.

These simple analysis may answer your question in a simple manner.

Best wishes

Thank you Abdelhalim abdelnaby Zekry . So, the voltage I plug in here is 110 V as that is the voltage we use in US/Canada or this volatile value is different then the main voltage. When we test VSWR of the antenna using network analyzer, the voltage in network analyzer is 110 V or DC voltage. which Number should I use for voltage or current is confuses me.

thank you

Dear Meenakshi Kohli

The voltage applied to the antenna is a radio frequency voltage. The antenna is either to transmit or receive the electromagnetic radiation and it fed by the rf transmitter or it receives waves from the air. The antenna is not fed either by the DC voltage or the mains voltage. These are used to power the equipment and instruments. What the output voltage from the network analyzer during you measurements?

What is your transmitter power??

Best wishes

Abdelhalim abdelnaby Zekry oh, I actually did not know I can check power from the network Analyzer. Could you please guide me also, how can I check the power from network analyzer. This actually clears my doubt a lot. Thank you

Dear Meenakshi Kohli ,

Welcome again,

The network analyzer outputs power at the input of the device under test. This input power is in dbm and can be adjusted.

It issues a range of values. may be up to 10-30 dbm.

You can consult the vendor if the values are not given in the data sheet.

But you must be aware that you can vary the input power levels while measuring S11 of your antenna.

So, in order to solve this problem, tell me what is the output power of your transmitter and what is the ratings of your antenna.

This depends on the application.

For your information the mobile phone antenna power is about 26-30 dbm.

Best wishes