New Innovation will Reduce RF Filter Costs for High Power 4G Devices

Resonant Inc. has announced an RF filter design innovation that allows the design of high-power RF filters using low-cost surface acoustic wave (SAW) processes. This breakthrough will first impact the fast-growing market of 4G high power user equipment (HPUE) devices. The HiPower SAW innovation was enabled by Resonant's high-precision Infinite Synthesized Networks (ISN) RF filter design tool.

Currently, Tier 1 4G smartphones have between 50-90 RF filters to support multiple antennas and radio frequencies needed for worldwide operation. Lower-cost processes will significantly reduce the bill of materials (BOM) cost.

HPUE devices, which are classified as power class 2 and operate at +26 dBm, were first announced by mobile network operators Sprint and China Mobile. Sprint, in particular, has actively promoted its HPUE strategy saying it allows the company to expand the coverage range of its 2.5 GHz cell sites by 24% and to offer 49% faster download speeds when compared to its 1.9 GHz network.

Resonant Details Innovation in New Whitepaper

Resonant has documented the performance of the HiPower SAW innovation in a recently posted whitepaper titled: Mobile Filter Innovation is Alive and Well in Extending the Reach of 4G. All filters that pass high RF power experience self-heating that limits the filter's maximum power. Through very precise simulation, Resonant is able to improve the power durability performance of filters made using the HiPower SAW designs.

This was shown by the results of a test described in the whitepaper which measured the power output of a standard SAW Band 3 transmit (Tx) filter and the Resonant HiPower SAW Band 3 filter as the input power was increased incrementally. The tests showed a linear progression for the SAW part until 32.5dBm of input power. The HiPower SAW part, however, continued its linear power performance up to an input power of 35dBm. Both of these power results were layered over simulations of the parts conducted by ISN, which predicted the power results very accurately. The innovation is good news for Resonant as the market for 4G filters is still growing across the world, and demand for 4G filters will be strong even in 5G phones.

Click here to download the white paper.