Parallel-plate line mode

Hi,

Can anyone explain briefly what is PPL meant and how can this occurs?
Anyway to prevent it?

Thanks.

it is a TEM (transverse electromagnetic mode) wave excited between two plates separated by any distance. as tem wave it has no cutoff frequency. graphically is similar to a TE10 mode excited in a waveguide, although you dont have the decay at the borders of the guide

it can be excited in a stripline due to leakage from the center conductor. and it usually affects the distribution of amplitude and phase of a feed network made on this technology (causes ripples, mismatch and so on).

one method to avoid the propagation of this ppl is to "box" the feed network distribution central line making a sort of waveguide which confines your feed network.

camel shalom,

Try to put the strip in the middle of the plates (in the z axis).
You can compute the SL to PPL mode using HFSS and study the effects of different configurations.

Itai

Could you try to explain in a more detail way? Sorry for my shallow understanding.