Low-profile, wideband electronically scanned array for geo-location, communications, and radar

A phased array antenna comprising:

• a plurality of unit cells, wherein each unit cell comprises:
• a base plate;
• a first ground clustered pillar projecting from the base plate, wherein the first ground clustered pillar is cylindrically shaped;
• a second ground clustered pillar projecting from the base plate and spaced apart from a first side of the first ground clustered pillar, wherein the second ground clustered pillar is cylindrically shaped;
• a first ground member projecting from the base plate between the first ground clustered pillar and the second ground clustered pillar, wherein a distal end of the first ground member is configured to capacitively couple to the second ground clustered pillar;
• and
• a first signal member projecting from the base plate between the first ground clustered pillar and the first ground member,
• wherein a distal end of the first signal member is configured to capacitively couple to the first ground clustered pillar, and wherein a portion of the first signal member facing the first ground clustered pillar is semi-circular so as to wrap around the first ground clustered pillar,
• and wherein a shape of the first signal member and a shape of the first ground clustered pillar are configured so that a distance between each adjacent unit cell of the plurality of unit cells of the phased array is greater than one half of a maximum operating wavelength of the phased array.