Explanation of insertion loss and return loss

Hi all,

In PCB or in EM field, if insertion loss is 3db, what does that mean. is it 3% of the signal are lost because of the insertion of a device?

Similarly 4% of return loss means what?
More the return loss os good?

Can anybody tell me?

Mani

insertion loss and return losses are always bad. These losses mean you loose signal power. These values should always be has low as possible.

-3 dB = 10^(-0.36/10) = 0.5 . This means your signal power was reduce to half.

i think thats not the case for return loss. return loss is the power reflected over power transmitted. so a -40db of return loss is better than -20 db. but this is not true for insertion loss.

anyway thanks.

Vswr when measured in dB gives return loss. IL measures the energy absorbed by the transmission line in the direction of the signal path in dB/m.Il of a cable varies with frequency;higher frequency means greater loss.high Il in feedline or jumpers can contribute to poor system performance and loss of coverage.