US Patent 11764466 Radio frequency witness film apparatus and system

The embodiments are directed to radio frequency witness films. The embodiments include a unit cell in a three-dimensional coordinate frame of reference defined by an x-axis, a y-axis, and a z-axis. The unit cell is centered at an origin of the three-dimensional coordinate frame of reference. The unit cell includes a substrate, a first conductive layer, a dielectric layer, and a second conductive layer. The second conductive layer has at least two microstrip extensions that are perpendicular to each other in the x-y plane.