Designers of PCB systems targeting wireless communications and sensing applications must integrate RF front-end technology within mixed-signal electronics. Engineering teams need a dedicated RF/microwave circuit design platform that is seamlessly compatible with their back-end tools. Offering a layout-driven methodology for developing complex RF PCBs, the Cadence® design solution, including AWR® RF/microwave design software, the Clarity™ 3D Solver, and Allegro® PCB Designer, supports such a workflow with accurate modeling of PCB transmission media from the RF signal path to digital control and DC bias lines, complete PCB system analysis, and manufacturing signoff.
Circuit/system and electromagnetic (EM) co-simulation provides first-pass design success with complete PCB analysis/EM verification of surface-mount components, interconnecting transmission lines, and embedded and distributed passive elements, along with an enterprise-level layout tool for RF/mixed-signal integration.
At high frequencies, electrical behavior is linked to the physical attributes of a design’s layout, along with those of the individual components. Design entry via schematic/layout capture enables you to define these circuit details for use in simulation, while automation and powerful scripting reduce manual design entry/editing and support data import and export between tools. After simulation, RF design tools must be able to export production-ready data or interoperate with other layout and analysis tools for any additional digital/mixed-signal design integration, manufacturing flow requirements, and final signoff.
Simulation for RF PCB Subsystems
Prior to manufacturing, board designs must be verified through computer-aided simulation and analysis. RF/microwave electronics rely on specialized measurements such as noise figure (NF) and small-signal transmission and reflection parameters (S-parameters), as well as their nonlinear power, gain compression, and efficiency response to large-signal stimuli. Most RF PCB designs rely on frequency-domain analysis of both linear and nonlinear networks, such as filters, power amplifiers (PAs), and frequency converters (mixers).
With the advent of digital modulation for communications systems, you may also need to analyze RF front-ends using circuit envelope analysis to simulate metrics such as adjacent-channel power-ratio (ACPR) and error-vector magnitude (EVM). In addition, RF budget and spurious heritage analyses are needed to provide cascaded performance measurements of multicomponent RF signal chains.
Model Library Support
Apart from modeling signal traces and distributed components, RF board designs require accurate high-frequency vendor models that capture parasitic behavior leading to self-resonance and other non-ideal characteristics. RF-aware design tools should provide component model libraries for commercially available discrete and packaged monolithic microwave IC (MMIC)/RFIC devices in the form of equivalent (compact) circuit models, S-parameters, and/or behavioral models.
RF design and enterprise-level PCB tools must support model libraries and design data that is recognizable across platforms, enabling different engineering teams and project stakeholders to accelerate time to market and gain the competitive advantage.
PCB designers rely on circuit/EM co-simulation, along with RF-aware circuit simulation and frequency-dependent transmission-line models, to provide embedded parasitic extraction and design verification. Hierarchical EM/circuit/system co-simulation enables you to perform in-situ EM analysis to capture and correct harmful parasitic couplings and resonances before tapeout.
Historically, large structures have been manually subdivided into smaller structures for EM analysis with existing compute resources, leading to higher engineering costs and potential errors. By adopting 3DEM analysis based on industry-leading parallelization technology, you can perform “golden standard” analysis and verification on the entire PCB and critical interconnects. Large-scale EM analysis that performs meshing and frequency sweeping through partitioning and parallelization across all available computing resources, configurations, and cores saves time and enhances accuracy.
Cadence software offers a leading front-to-back RF PCB design flow with an innovative user interface and complete integration of design entry, simulation, and physical design tools that enhance productivity and ensure first-pass success.
The Cadence AWR Design Environment® platform provides RF/microwave engineers with integrated high-frequency circuit, system, and EM simulation technologies and design automation to develop physically realizable electronics ready for manufacturing.
Cadence Microwave Office® circuit design software offers an intuitive interface, innovative design automation, and powerful harmonic-balance circuit simulation to ensure greater engineering productivity and accelerated design cycles.
Cadence Visual System Simulator™ (VSS) RF/wireless communications and radar system design software supports voltage standing-wave ratio (VSWR)-aware modeling of RF and digital signal processing blocks, providing time-domain, frequency-domain, and circuit-envelope analyses. Simulation with preconfigured and/or customized system testbenches provides analysis of adjacent channel power ratio (ACPR), bit-error rate (BER), and error vector magniture (EVM) for PCBs operating under wireless, standards-specific, modulated waveforms.
The Cadence AXIEM® 3D proprietary full-wave planar EM simulator is based on method-of-moments (MoM) fast-solver technology that eadily analyzes distributed PCB components, transmission lines, and layer-to-layer PCB interconnects such as vias. Designers can extract S-parameters directly within their PCB design and visualize fields/currents to identify parasitic coupling and resonances.
Industry-leading distributed multiprocessing technology enables Cadence's FEM/finite-difference time-domain (FDTD) Clarity™ 3D Solver to deliver the virtually unlimited capacity and 10X speed required to efficiently and effectively address larger and more complex structures. The solver creates highly accurate S-parameter models for use in RF/microwave, signal integrity (SI), power integrity (PI), and electromagnetic compliance (EMC) analyses.
The Allegro PCB Designer and AWR Design Environment platforms combine to bring your innovative wireless designs to life. With a comprehensive, powerful, and easy-to-use suite of tools, you can effortlessly tackle the simplest or most complex projects. The constraint-driven environment provides real-time visual feedback and ensures the functionality and manufacturability of your PCBs while reducing design time.
Microwave Office v16 converts Allegro PCB Designer's component symbols, footprints, and technology board files into an AWR process design kit (PDK) that can be used to create an RF design using standard design entry and simulation methods. Upon completion of the design, you can export the schematic and layout of the sub-circuit with all the underlying hierarchy into a design library accessible to the layout engineer working in the Allegro PCB editor.
By starting with Allegro PCB Designer-sourced component parts from an organization’s approved bill of materials (BOM) and process technologies, the RF engineering and layout teams improve design handoff efficiency/reliability and reduce the amount of back and forth necessary to reconcile differences between RF design and manufacturing requirements.
For high-frequency designs, Allegro PCB Designer provides a robust set of layout functionalities including parameterized etch element generation, quick placement, RF-style routing, editing of RF etch elements, and the ability to place via arrays along user-specified objects such as an RF component, a connect line (cline), or a discrete component.