MtronPTI Rolls Out New ISM Band 915MHz SAW Filter

Cashing in on the bolstering 4G/LTE and smart grid markets, Florida-based MtronPTI – a provider of frequency control and filter products – has introduced a new ISM band 915 MHz RoHS Surface Acoustic Wave (SAW) filter, SF2620R, tailor-made for applications in the 4G/LTE wireless infrastructure, sensor networking and smart grid markets.

Generally, SAW filters are electromechanical devices generally used in radio frequency applications. The devices are well-known as a rugged low cost means to offer a variety of signal processing functions covering a frequency range of 20MHz to 2.5GHz. The applications can range from as small as 0.01 percent in fractional bandwidth for resonators to as large as 50 percent for wideband filter requirements.

Some of the popular applications for SAW filters, as cited in the company’s website, include bandpass filters (RF and IF) for spectral shaping with image rejection, delay lines, coded waveform generation, correlators and resonators for phase noise clean up in synthesizers, and more.

The latest offering by MtronPTI, SF2620R, is a new ISM Band 915 MHz RoHS SAW Filter featuring a small form factor of 1.4mm x 1.1mm x 0.7mm and a typical 3dB bandwidth of 26MHz, thereby making it ideal filter for wireless data transfer applications generally associated with Smart Grid sensor and data collection networking.

In addition, the new SF2620R SAW Filter features >40dB rejection at 846MHz and 990MHz. This insures that a wireless system using the SF2620R meets all FCC requirements for adjacent channel interference mitigation for a device utilizing the license-free ISM band.

According to MtronPTI, a SAW Filter encompasses of Aluminum patterns deposited on a piezoelectric substrate that is wire bonded to a hermetically sealed package connecting it to a PCB. Generally, it consist of an input and output transducer that is composed of an interdigital structure. In many cases the package is externally interfaced on the board with input and output matching elements to transform the SAW impedance to the source and load impedance.

Inside a SAW Filter, electrical signals are converted to a mechanical wave with the piezoelectric crystal or ceramic. The acoustic wave then propagates along the surface of the material to the output Aluminum pattern where it generates an electric field between the Al elements producing a time delayed spectrally shaped signal at the output.

According to MtronPTI, the minute size of the SF2620R provides the system wide latitude in the application of the SF2620R, without concern for the wireless platform target. In addition, the combined outstanding electrical and environmental performance characteristics along with the small footprint of the SF2620R, several applications can take advantage of this product's performance specifications, including base station data collectors, vehicle mount remote readers, handheld readers and/or Smart Grid wireless utility meters, or the smallest of wireless sensors.

Bruce Mackie, senior applications engineer, said in a statement, “The ultra-small size, coupled with the outstanding performance characteristics of this product, frees the ISM band RF Design Engineer of concerns for overall system performance and will enable the inclusion of additional end product functionality, as well as the potential to reduce filter costs.”

In other news, MtronPTI had exhibited at the IEEE MTT-S International Microwave Symposium (IMS 2011) held in Baltimore, MD, earlier this year.