What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/4-wavelength apart and fed 90 degrees out of phase?

A cardioid pattern resembles a heart shape, featuring one large main lobe in one direction and a deep, singular null in the exact opposite direction. This specific pattern is created by balancing the physical travel time of the wave with an electrical delay. When two vertical antennas are spaced 1/4-wavelength apart, it takes 90 electrical degrees for a signal to travel between them. If they are also fed 90 degrees out of phase, the wave traveling in one direction along the axis experiences a 90-degree physical delay plus a 90-degree electrical delay, totaling 180 degrees and completely canceling out. In the opposite direction along the axis, the 90-degree physical delay offsets the 90-degree phase lead, bringing the signals perfectly into phase. Because the signal adds entirely in one direction and cancels entirely in the other, a cardioid shape is formed, making the distractors describing figure-eights or omni-directional patterns incorrect.