e cross h
Dear sanders,
This is something I'm quite familiar with...
Think of an AUT (e.g. patch antenna) in an anechoic chamber on a turn-table, and always remember:
E-plane of the AUT is its plane parallel to the direction of its current flow. With this in mind, this antenna's orientation is subsequently placed in parallel to the rotation of your turn-table. Now, all measurements will be in the E-plane.
To get H-plane, naturally, it is orthogonal to the E-plane.
E-plane Co-pol and E-plane Cross-pol is the AUT's E-plane Co- and Cross-polarisation patterns respectively (with respect to the orientation of your reference antenna and its corresponding current flow too). Co- and Cross-pols are again orthogonal to each other.
Gain patterns are supposed to be of the same shape as radiation patterns, hence, that's why some people uses this form of interpretation (i.e. when compared to the traditional E-theta or E-phi). And also, some people use E-co/H-co because it is much simpler to use on antennas that radiate in one-direction (e.g. patches)
Now, from above, its relationship to E- or H-fields is pretty straight-forward to visualise.
Hope this helps,
Dave