Gradient’s parameters:

Make a copy of the recently created layer and make use of the Free Transform selection to minimize it a little, turn it around and place it the same way it is demonstrated in the lower picture. Don’t forget to change a little the layer’s adjustments.

Fill 0% on the layers.
Blending Options-Gradient Overlay

Apply the instrument to draw that special ball on the antenna’s tip.

Blending Options-Gradient Overlay

Gradient’s parameters:

Copy the new represented layer and make use again of the Free Transform option to minimize it and place it on the opposite antenna’s tip.

The final result!