Bulk Acoustic Wave (BAW) Filter Technology


Bulk Acoustic Wave (BAW) filters show vital roles in wireless devices and infrastructure. They make sure separation between the ever-developing number of frequency bands and deal low insertion loss to support device routine supplies.

Though, the worldwide rollout of 5G, and the development of other wireless standards for example Wi-Fi, generate new filtering challenges that are outside the competences of old-style acoustic filters. Noteworthy developments in BAW technology were necessary to resolve these new tasks.


The BAW filter changes an electrical input signal to an acoustic wave by using interdigital transducers (IDTs) on a piezoelectric substrate similar to quartz. The interdigital transducers (IDTs) are invented of interleaved metal electrodes. That inaugurate and obtain waves. That transforms an electrical signal to an acoustic wave and then back to an electrical signal.

The BAW filters are developing to care higher frequencies and better bandwidth for the new 5G and Wi-Fi band growth. Complex multi-filter modules for example multiplexers and antennaplexers are being used to control the challenges, mainly with 5G.

The structure of the BAW device

Bulk Acoustic Wave (BAW) Filter Technology

The basic construction of the BAW device is very simple. It is generally composed of a piezoelectric stack on a silicon substrate. The piezoelectric stack is comprising;

  • A bottom electrode
  • A piezoelectric film
  • An upper electrode.

The likeness in the structure of the electrode forms a standing wave resonance. The dominant layer of TI BAW resonator technology is a piezoelectric material. This will grounds the mechanical structure to vibrate when a frequency is applied to the device. Now, the layer structure will seizure the made energy. The important attribute of the BAW resonator is to have the extreme acoustic energy in the storage structure that is used to get a high electrical Q factor value.

What is a Power Filter (PF)?

  • The power filter (PF) is a filter circuit. That is composed of capacitors, inductors, and resistors.
  • The filter may successfully filter out the frequency point of a particular frequency in the power line or the frequency other than the frequency point to achieve a power signal of a particular frequency, or remove a power signal of a precise frequency.
  • A filter device is used to filters waves. The wave is a wide-ranging physical concept.
  • The wave is closely limited to exactly refer to the process of fluctuations in the values of many physical quantities over time.
  • This process is changed into a time function of voltage over the action of numerous sensors. That is called the time waveform of several physical quantities or called signals.
  • Nowadays wireless devices must at the same time lookout against interference signals from other devices and themselves by the growing number of frequency bands held in each device.
  • A high-end smartphone need filter the transmission and reception paths of up to 15 frequency bands of 2G, 3G, and 4G wireless access methods.
  • All at once, the filtering similarly take in Wi-Fi, Bluetooth, and GPS receiver response tracks.
  • The signal of individually receiving path must be inaccessible. It is similarly essential to overpower other outside signals that have numerous sources and are tough to quote.
  • A multi-band smartphone needs eight or nine filters and eight duplexers to do this.
  • This would be challenging to do deprived of acoustic filtering technology.

Main Features of BAW Filter Technology

High Frequencies

BAW Filter technology traditionally well above the range support the high frequencies.

Heat Dissipation and Reliability

BAW filters are the greatest small size technology to dissipate heat. That supports to enhance reliability of the filter.

Better Bandwidth

BAW filters helps to increase bandwidth assigned to 5G bands.

Reduced Size

BAW filters become smaller and additionally joined to fit into the narrow space available in devices.

Lower insertion Loss

Due to the introduction of 5G, demand has increased for filters with lower insertion loss.

Bigger rejection

Great increase for filter technology to support coexistence is necessary with the extra 5G spectrum re-farming and crowding.