Thin film bulk acoustic resonator
Encyclopedia
Thin Film Bulk Acoustic Resonator (FBAR or TFBAR) is a device consisting of a piezoelectric material sandwiched between two electrode
s and acoustically isolated from the surrounding medium. FBAR devices using piezoelectric films with thicknesses ranging from several micrometres down to tenth of micrometres resonate in the frequency range of roughly 100 MHz to 10 GHz. Aluminium nitride
and Zinc oxide
are two common piezoelectric materials used in FBARs.
(SAW) devices, due to smaller size and increased fabrication and operating efficiencies.
FBARs can be used by microwave oscillators.
FBARs can be used in sensor applications. For instance, when a FBAR device is put under mechanical pressure its resonance frequency will shift.
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
s and acoustically isolated from the surrounding medium. FBAR devices using piezoelectric films with thicknesses ranging from several micrometres down to tenth of micrometres resonate in the frequency range of roughly 100 MHz to 10 GHz. Aluminium nitride
Aluminium nitride
Aluminium nitride is a nitride of aluminium. Its wurtzite phase is a wide band gap semiconductor material, giving it potential application for deep ultraviolet optoelectronics.-History:...
and Zinc oxide
Zinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...
are two common piezoelectric materials used in FBARs.
Applications
A common application of FBARs are radio frequency (RF) filters for use in cell phones and other wireless applications. Such filters made from a networks of resonators (either in half-ladder, full-ladder, lattice or stacked topologies) and are designed to remove unwanted frequencies from being transmitted in such devices, while allowing other specific frequencies to be received and transmitted. FBAR filters can also be found in duplexers. They have partially replaced an earlier technology based on surface acoustic waveSurface acoustic wave
]A surface acoustic wave is an acoustic wave traveling along the surface of a material exhibiting elasticity, with an amplitude that typically decays exponentially with depth into the substrate.-Discovery:...
(SAW) devices, due to smaller size and increased fabrication and operating efficiencies.
FBARs can be used by microwave oscillators.
FBARs can be used in sensor applications. For instance, when a FBAR device is put under mechanical pressure its resonance frequency will shift.