Infinite Synthesized Networks (ISN®)

How we do it

Proprietary design tools (ISN®):

The company’s large suite of proprietary mathematical methods, software design tools and network synthesis techniques enable it to explore a much larger set of possible solutions and quickly derive the optimum solution.

These improved filters still use existing manufacturing methods (i.e. SAW, temperature compensated (TC) SAW & BAW/FBAR) and depending on the requirements and capabilities of the given foundry, the company’s technologies have the ability to improve design efficiency through shorter design times and deliver designs utilizing lower cost manufacturing processes with performance comparable to designs using higher cost methods (i.e. BAW/FBAR).

While most of the industry designs surface acoustic wave filters using a coupling-of-modes (COM) model, Resonant uses circuit models and physical models. Circuit models are computationally much faster, and physical models are highly accurate models based entirely on fundamental material properties and dimensions. Resonant’s method delivers excellent predictability, enabling achievement of the desired product performance in fewer turns through the fab.

Single-Band Designs

Some of the single-band filter designs are for duplexers that have historically been TC-SAWs or BAWs while others are for discrete SAW filters that may need improvements in performance, size or cost. The single-band designs included “Wi-Fi Co-Existence” filters, which pass licensed wireless frequencies, while protecting Wi-Fi from interference, and designs for module applications which require wafer-level (WL) packaging and modeling of the module board. Using the ISN technology, combined with Resonant’s experience and know-how, the company can design innovative SAW filters that meet the performance requirements for many of these bands but at significantly less cost than that of BAW filters or even TC-SAW filters they would replace.

Multiplexer Designs

Wireless carriers worldwide are experiencing increasing demand for higher data speeds. Carrier aggregation (CA) allows multiple data streams from different frequencies to be added together to provide increased data rate for mobile device users. However, CA further complicates the required filter characteristics. Quadplexers (which multiplex four RF paths) enable CA on both receive and transmit paths and reduce the RF front-end complexity by removing switches. But complexity of the filter functionality increases dramatically. Resonant’s ISN technology is ideally suited to these difficult filter design problems that covers a wide frequency range with much more demanding performance requirements. The company is developing a family of high-performance multiplexer designs to address this growing market.

Advanced Developments

ISN technology will also enable Resonant to design novel filters that are more than simple replacements, but rather can enable an architecture change, or can provide a step function improvement in performance, size and cost to a handset manufacturer. These include:

  • Triplexers/Multiplexers - wideband, low loss multiplexed filters which allow efficient sharing of antennas. As more spectrum becomes available above 2.5GHz, the focus will be in minimizing the losses at the higher frequency.
  • Multi-passband Filters - small size, low loss filters to maximize PCB space and minimize loss, particularly suited for CA applications. No switching elements further reduces size and cost for CA.
  • XBAR - high performance resonator technology developed using ISN for filters for 5G NR devices, Wi-Fi systems and millimeter wave systems. See more information on XBAR here.

Resonant delivers designs to the foundry in a language they understand:

Because Resonant’s models are fundamental, integration with its foundry and fab customers is eased because the models speak the “fab language” of basic material properties and dimensions. In addition, through its ISN Foundry Program, Resonant has pre-qualified a number of fabs, back end and packaging firms for faster production times.

Legacy COM filter designs are delivered to the foundry with definitions of aggregated physical properties, which requires the fab to figure out how to produce the filter. Resonant delivers the complete recipe to produce its filter designs, including basic material properties, density and dimensions.