A radio frequency device, comprising: a first dielectric layer of a dielectric material, the first dielectric layer having a first surface and a second surface opposing the first surface, the first dielectric layer having a first plurality of cavities, each of the first plurality of cavities extending between the first surface and the second surface; and a plurality of first filter unit cells formed at least partially in the first dielectric layer, each first filter unit cell comprising: a first plurality of sidewalls of a subset of the first plurality of cavities; first conductive sidewall layers (222, 224) formed on at least portions of the first plurality of sidewalls, the first conductive sidewall layers defining a first resonant space comprising some of the dielectric material, and the first resonant space being separated from the first resonant spaces of adjacent first filter unit cells of the plurality of first filter unit cells by respective single first cavity of the first plurality of cavities; a portion of a first conductive layer covering at least a portion of the dielectric material of the first resonant space and electrically connected to the first conductive sidewall layers (222, 224), the first conductive layer formed on the first surface of the first dielectric layer and common to the plurality of first filter unit cells; and a first radio-frequency input-output, RF I/O, contact formed on the first surface, the first RF I/O contact electrically isolated from the first conductive layer by a first isolation region formed around at least a portion of a perimeter of the first RF I/O contact. a first dielectric layer of a dielectric material, the first dielectric layer having a first surface and a second surface opposing the first surface, the first dielectric layer having a first plurality of cavities, each of the first plurality of cavities extending between the first surface and the second surface; and a plurality of first filter unit cells formed at least partially in the first dielectric layer, each first filter unit cell comprising: a first plurality of sidewalls of a subset of the first plurality of cavities; first conductive sidewall layers (222, 224) formed on at least portions of the first plurality of sidewalls, the first conductive sidewall layers defining a first resonant space comprising some of the dielectric material, and the first resonant space being separated from the first resonant spaces of adjacent first filter unit cells of the plurality of first filter unit cells by respective single first cavity of the first plurality of cavities; a portion of a first conductive layer covering at least a portion of the dielectric material of the first resonant space and electrically connected to the first conductive sidewall layers (222, 224), the first conductive layer formed on the first surface of the first dielectric layer and common to the plurality of first filter unit cells; and a first radio-frequency input-output, RF I/O, contact formed on the first surface, the first RF I/O contact electrically isolated from the first conductive layer by a first isolation region formed around at least a portion of a perimeter of the first RF I/O contact. a first plurality of sidewalls of a subset of the first plurality of cavities; first conductive sidewall layers (222, 224) formed on at least portions of the first plurality of sidewalls, the first conductive sidewall layers defining a first resonant space comprising some of the dielectric material, and the first resonant space being separated from the first resonant spaces of adjacent first filter unit cells of the plurality of first filter unit cells by respective single first cavity of the first plurality of cavities; a portion of a first conductive layer covering at least a portion of the dielectric material of the first resonant space and electrically connected to the first conductive sidewall layers (222, 224), the first conductive layer formed on the first surface of the first dielectric layer and common to the plurality of first filter unit cells; and a first radio-frequency input-output, RF I/O, contact formed on the first surface, the first RF I/O contact electrically isolated from the first conductive layer by a first isolation region formed around at least a portion of a perimeter of the first RF I/O contact.