Provided herein are devices, systems and techniques for establishing a variable height conformal antenna array having a planar backplane. More particularly, positioning of radiating elements can be made insensitive to variable ground height by selecting a suitable radiating element, such as a flared notch and arranging them to have a profile such that their outer extremities are positioned along a conformal, curved shape. Differences in radiator heights can be taken up by the addition of parallel vertical ground planes disposed between the radiating elements and the backplane. Adjacent vertical ground planes effectively form cutoff waveguide sections that naturally isolate the backplane from the radiating elements. The vertical ground planes edges effectively form a virtual curved ground for the radiating elements, following curvature of the array profile. Accordingly, heights of radiating elements are uniform with respect to the virtual ground, while being allowed to vary with respect to the backplane.