Increasing restrictions are one of the biggest challenges related to the growth of 5G applications, particularly shrinking the size and form factor of the components. Design engineers focused on filter designs must spend much time and effort to determine a resonator layout that will meet these dimensional requirements; the restrictions add risk to the design workflow, such as reducing the out-of-band rejection or power handling. To meet the size and weight requirements without sacrificing RF performance, designers must have greater design flexibility to consider alternative topologies. The challenge, however, is few software tools are available to help designers explore topologies and options that will meet the design goals.

SynMatrix is one of the most advanced RF filter design and test tuning platforms, which reflects the company’s mission to significantly reduce the time to engineer and manufacture complex RF filters. Pursuing this goal, SynMatrix has released several innovative functions during the past two years to accelerate the design workflow. Recently, SynMatrix released an upgrade for creating topology designs. Previously, users had the freedom to create and edit their own topologies by clicking on an easy-to-use graphical interface; however, this required having a thorough knowledge of filter design and topologies. To help less experienced designers, SynMatrix has introduced a library with thousands of practical topologies that can be selected to best fit the application.

This new integrated topology library (see Figure 1) includes several categories and types, including transversal, arrow, box section, inline, cul-de-sac, non-resonating node, extended box and multi-modes. SynMatrix’s topology library considers the more practical applications users may face, offering hybrid modes that mix different topology types.

Figure 1

Figure 1 SynMatrix topology library.

Figure 2

Figure 2 Graphical interface for generating the coupling matrix.

The design workflow begins with specifications, where designers input the filter order and transmission zero information. Then, users select from a large library of topologies and generate the corresponding coupling matrix. The coupling matrix can be generated from a standard topology list and, using an advanced coupling matrix reduction technique (see Figure 2), generate the coupling matrix from a mixed topology matrix. Examples of these mixed topology structures include the cascaded triplet (CT) or cascaded quadruplet (CQ) mixed with box section; non-resonating node mixed with CT or CQ; and multi-mode mixed with CT or CQ.

SynMatrix has implemented a thorough and comprehensive method to explore all possible combinations from these mixed topologies, generating thousands of possibilities from the different combinations. To maintain an easy-to-use experience without overwhelming users, SynMatrix offers a filter function within the graphical interface that helps users choose the desired topology by selecting a fixed coupling path (see Figure 3). This feature augments the current interface, so users opting to construct their own coupling and topology structures can still use the prior “check mark” table interface. This gives designers the full range of options, which they choose to best support their backgrounds or the application.

Figure 3

Figure 3 Interface for selecting the coupling path.

Figure 4

Figure 4 Completed filter simulation.

Using the same workflow and user experience, the new topology library supports several filter types, including multiband, diplexer and triplexer (see Figure 4). Considering data analysis and diagnostics, SynMatrix’s Computer-Aided Tuning (CAT) platform now supports more applications. Designers can use CAT to evaluate these newly supported topologies, such as box section and its mixed format, multi-mode and its mixed format, cul-de-sac, arrow and transversal.

The introduction of the SynMatrix topology library expands the flexibility for filter designers, with more capability to address the challenging design requirements driven by 5G. It increases design engineering capabilities, saves time in the development and helps identify and avoid downstream RF performance problems that may not be apparent at the start of the design workflow. By using a comprehensive set of tools and topologies, SynMatrix quickly unblocks many of the challenges facing design engineers, simplifying the design process and yielding more successful designs.

SynMatrix Technologies Inc.
Toronto, Canada