RE: PSpice model for 1/4 wavelength antenna

Hi Robert, SPICE is a time domain tool, you might have difficulty finding a suitable model as most antenna analysis is performed in the frequency domain. To find the radiation resitance and impedance of a monopole is easy using one of the NEC family of codes (Numerical Electromagnetics Code)

RE: apertures

One approach to take for small apertures in solid sheets is to reverse the model. That is model the equivalent dipole, you will have far fewer elements and no meshing issues. Due to the duality between E and H known as Babinet's priciple, this is vaild method. Check out slide 8 on this link:

RE: apertures

Hi, Another way of thinking about this is to consider the effective aperture of the slot antenna on the source side of the shield this will more easily give the amount of energy coupled into the antenna. However, remember that the shielding effectiveness equation is specific to planes wave

RE: NEC-2 simulations

CEM = Computation ElectroMagnetics. There are a number of us around using CEM for EMC design and anyalysis where appropriate. The ACES group (Applied Computation Electromagnetics Society) have a session dedicated to EMC at their annual conference in Monterey, CA. (It's next week - if you hurry

RE: Question on Receiver EMI testing..

Hi Charles, I have seen some other replies but I understood your question differently. Are you trying to test the receiver or is it simply a remote front end for your measurement set? I don't know anything significant about the first, but if it is the latter then the receive head should be

RE: limits of electrical modelling

Hi Muriel, You may need to use full 3D modeling to get evaluate stray L C and even R but unless the object that you are examining is electrically large (say .1 wavelength or more) you should not need a full wave tool for a SMPS. Lumped elements can be used even at very high frequencies

RE: physics behind EMI powerline filter

Hi Muriel, I think the answers so far have given you some good ideas. There are number of different things that can happen. Filter design should not be considered as completely separate from the system design especially in a power supply. First, by providing a low impedance to the power

RE: Pre-amps

Greetings, I believe David is correct here, the effect of the mismatch between antenna and preamp is still there and so all the available energy from the antenna will not be transferred to the preamp. However, the effects of the length of cable will be gone as with zero length there can be no

RE: Metrics

Hi, One metric that is missing is the cost of over-design. As we all know EMC design is not quite a precise science :) but it is relatively easy to make anything comply first time if cost, and size are ignored! Depending upon the cost sensitivity of the product you might not want to pass

RE: Horizontal Antenna

Hi David, You cannot ignore the ground plane at all. It would be better to think of the transmit antenna as two separate antennas at 1m above and, 1m below, the level of the ground plane and then you can ignore it to some extent. You will always see the combination of these two sources. Simply

RE: Shielding Effectiveness Question

Greetings Neven, There are a couple of things that need to be considered when you have an rf source close to a shield with apertures. First is the shielding properties of the shield as people have said this is very dependent upon the field impedance when you are in the near field. Second and