Study Decoupling between two antenna

Mohamed AHMED

I’m trying to study the decoupling between two antenna  VHF antenna and UHF/VHF antenna.

 

First antenna:

 

VHF antenna Band is (30 -88 MHz)

 Power (0.28 W, 5 W, 50 W)

Length of antenna is 

3.3 m

 Antenna Characteristic

Second antenna:

UHF antenna Band is   (100–500MHz)

                                 (500 - 1300 MHz)

 Power (AM 32 W – FM 100 W)

 Antenna Characteristic:

 

They ask for 12 dB of decoupling at 1.3 m of distance between the two antennas.

 

“” the necessary minimal decoupling to allow the simultaneous functioning transmission/reception, with a degradation of range on the received signal lower than 35 %, is 12 dB””

 

Also,

 

“The equipment situated in the neighbourhood of the antenna shall bear the RF field radiated

transmitting at maximal power (50W). This field can reach 60 V/m ata distance of 1 meter from the antenna”

 

“The installation shall not radiate broadband parasites which level is higher than 10dBμV/m, in the

neighbourhood of the antennas (0.50 m)”

 

Do you have any ideas how we can study this case?

Mel

Feko can be used for the decoupling modelling:

You will need to create models of the two antennas. 

Once you have models of the two antennas, then you should create an S-parameter request and check the value of S21 in dB. This should be smaller than -12 dB.

As for the equipment, the manufacturer should be able to comment on the EM susceptibility of the equipment and its electronics.

A simple shielding test is to model the outside of the equipment, maybe this is a PEC box, with small holes. The source would be the antenna, set to radiate 50 W of power. Again, whether the electronics inside can handle these fields is for the manufacturer to say.