Antenna with different receive and transmit impedance

[cadour]

Hello,

generally, by design, the receive and transmit loads of an antenna would be the same. Is there a way to have differing loads in transmit and receive modes?

I.e. I want an antenna to be highly reflective to incoming signals but be ideally parametrised when transmitting.

Thanks for any suggestions or help

Cadour

 

[VEBill]

What's the application?

 

[cadour]

Trying to understand antennas in stealth airplanes where I would think you would want the antenna to reflect as little as possible (the opposite of my question )

 

[VEBill]

Hmmm...

In answer to the original question, you'd probably use a simple T/R switch at the feedpoint. When transmitting, the transmitter would be connected straight through. When not transmitting, the "receive" path would be a refective short.

There may be other techniques that could be used such as circulators or quarter-wave directional couplers.

What these all have in common is that the action happens in the feed line, not the antenna as such.

 

[IRstuff]

see:

http://wstiac.alionscience.com/pdf/WQV8N2_ART05.pdf

for a discussion about this

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[cadour]

Thanks VE1BLL and IRstuff for your help.
Interesting that Plasma antenna- what a brilliant idea (litteraly).