Abstract: Provided herein is a unit cell for a phased array antenna. The unit cell can include a base plate and a shell. The shell can include a plurality of spectrum element cavities, with each spectrum element cavity comprising a post. An inner surface of each of the spectrum element cavities can be coated with a conductive material such that the spectrum element cavities form a signal ear and a ground ear of the unit cell. The base plate can be configured to provide a path to ground and include a plurality of holes. The shell can be aligned with the base plate such that the post of each signal ear of each spectrum element cavity is aligned with one of the holes of the base plate.