Receiver positioning challenge

[rodgerwxh]

Hi folks:

I have a challenge in hand, the goal is to use a new device as a receiver (not traditional metal antennas). Such receiver is put on the side of a large platform. The challenge is to allow the incoming wave completely pass through the receiver without any reflection. But the large platform (PEC walls) is necessary for the receiver to mount on.

Thus I have no clue of how to achieve this. Maybe put a wave absorbing media behind the receiver? But do we really have that kind of material in real life? And is it reasonable to put that thing behind?

The other thing I am thinking is to cut a whole on the platform right behind the receiver, however this is not working since the wave will still be severely reflected.

I need help from antenna experts to instruct me that if this is doable, any typical prototypes to handle this kind of thing?

Thanks in advance.

 

[chuckey]

There is a carbon based (AquaDag) paint that has the same conductance as free space. it is used to paint structures around airfields to stop radar reflections.
Frank

 

[jiripolivka]

I do not understand your problem: do you need to make the platform invisible for a radio wave, or the receiver?
If the receiver is small respect to the wave length, you can locate it behind the conductive platform, so most of wave field is reflected from the platform only.
To make objects invisible to radio waves, you can use the above advice or find a suitable foam absorber to cover an object. Then it will not reflect the wave back.
A modern way is to use special structures to make objects "invisible".

 

[rodgerwxh]

Thank you Jiripolivka, I want the object invisible so that the incoming plane wave only go through the receiver and sees nothing else.

Following your advice, in order to make the object invisible, do we need to cover the entire platform with foam absorber? or we only need to cover a small area. Since the receiver is very very tiny compared with wavelength and object size. I want to know a practical and operable plan for this. Thanks a lot.

 

[jiripolivka]

I would advise to run an experiment to see if and how well the absorber does the job. I have not seen any indication of the frequency to be used. The wavelength compared with object size is important.
Eccosorb and other companies making absorbers can offer a good solution: absorbing mats or boards, foam or mesh. Their reflectivity and absorbance is frequency and angle-dependent, therefore only an experiment will show a good solution.