5G Microwave-RF EDA Design Flow

PathWave Advanced Design System (ADS) streamlines multi-technology IC-package-board design of densely integrated RF modules

PathWave Advanced Design System (ADS) addresses 3 critical requirements for 5G product development that had not been satisfactorily met by other EDA tools in the market before. These are:

• Assembling and performing 3D EM-circuit co-simulation on multi-technology 5G modules

• Designing for modulated signals and verification against 5G modulation standards

• Stability analysis of large signal multi-device amplifiers

Industry trends towards ever higher frequencies, digital modulations and complex integrated systems – The Implications

Going from 4G to 5G, frequencies have increased by a factor of 40 (700 to 2600 MHz to 28 to 40 GHz), while automotive radar frequency bands are going from 24 GHz to 77 GHz. Not only are frequencies increasing, so are the density and complexity of system integration such as the inclusion of phased array antennas. Digital modulations have also replaced traditional analog schemes. These trends have significant implications on the design of components and systems for RF/MW applications, namely:

• Design flows need to support assembly and interconnect of multitechnology components (RFICs, MMICs, wafer-level package, phased array antennas, laminates and PCBs) into dense, complex RF modules. The flows must then include verification by entire module level DRC (Design Rule Check) and LVS (Layout vs. Schematic) for manufacturing sign-off.

• Electromagnetic effects of dense, complex system integration at mmWave frequencies degrade circuit performance such as loss, coupling, and frequency shifts. Circuit designers need to interactively include 3D EM effects of packaging and interconnects during design exploration, tuning, and optimization – not just for final verification of the completed design.

• Digitally modulated RF signals require new figures of merit for circuit design and optimization, the most important of which is distortion EVM (Error Vector Magnitude). Traditional analog rules of thumb or relying on instruments that were adequate for 3G, and barely adequate for 4G, will lead to off spec or over-design of circuits for 5G digitally modulated signals.

• Since transistor gains roll off at higher frequencies, overall gain must be increased to offset this. High gain amid dense integration is a recipe for unintended coupling that often cause unstable amplifiers. Analyzing instability in amplifiers operating under nonlinear large signal conditions is now required to avoid building costly unsalable amplifier hardware in an extremely competitive market.

The Consequence

The consequence of the above implications is that current existing flows are no longer adequate to achieve wins for the 5G, automotive radar and aerospace/defense market.

• Engineers can no longer design pieces of their system on a standalone basis; but need to consider effects which span from the transistor all the way out to the antenna far field radiation pattern.

• They need to assemble circuit, EM, and electrothermal analyses together across technology boundaries.

• It is not trivial to assemble IC’s with packages in the design tools in the first place, but to do that in a way which facilitates EM and circuit envelope analysis to understand the effects of modulated waveforms in a multi-technology 3D structure is nearly impossible using existing EDA tools.

After witnessing how RFIC, RF module, and RF PCB designers struggle to correctly assemble and setup ICs, packages, and interconnects for 3D EM-circuit co-simulation to meet 5G and automotive-military radar modulated signal specs, Keysight significantly enhanced PathWave ADS by deploying its expertise across measurement and simulation domains to uniquely address these extreme difficulties.