Two element Controller Plots 

This array will be about 1 db down from a full size 4 square and have about the same front to rear rejection.

Two Element Array controller by Array Solutions

Two Element Array Spaced 1/4 WL Apart

fig 1  Two Element Array 80 meters

The above two vertical array is modeled with 30 radials under each antenna. The spacing of each vertical is .25 wavelengths from each other.  The array is driven such that both are in phase or one element is lagging the other by 90 degrees. 

The following Plots (fig 2 and fig 3) for this array are for both elements being fed in phase or the broadside mode.

They achieve maximum lobe take off angle of 20 degrees above horizontal over medium ground 

fig 2 

fig 3

The next set of plots is for the same array in fig 1 but using a delay of 90 degrees to create a cardioid pattern off the end of the array.  This is switchable in two directions.

fig 4 using -90 degree phasing delay between the elements

fig5 Azimuth of Cardioid pattern at 20 degrees above horizon

The Cardioid pattern can be steered in two directions off the ends of this array with this controller.  

If you wish to model the antenna yourself and adjust the phasing to your liking here is the EZNEC 3 model:  2 Element Array Model