May 18, 20265 min read

A focused CST alternative for planar PCB RF

Short answer

CST Studio Suite is a broad 3D EM package leased at roughly 14,500 to 22,000 USD per year by published figures. For planar PCB RF specifically, RayRF is a GPU FDTD tool at 1,499 USD per year with a GUI and live results. It does much less than CST, and it does the PCB slice fast.

CST is a serious tool with a serious scope: 3D geometry, multiple solvers, multiphysics, and a price to match. The honest question for a PCB RF designer is whether the work needs all of that, or whether it is patches, filters, couplers, and transmission lines that a focused tool can turn around quickly.

What CST gives you that RayRF does not

Arbitrary 3D geometry, not just planar PCB stackups.
Multiple solver types and multiphysics coupling.
A deep, mature feature set with decades of industrial use.

If your work needs those, RayRF is not a replacement and this post is not trying to talk you out of CST.

What RayRF does differently

RayRF is built for one job: planar PCB RF, done quickly. Draw or import the board, set the stackup and ports, slide a quality preset, and run on your NVIDIA GPU with the S-parameters updating live. The whole loop is one window, and a small edit-and-rerun cycle is seconds, not a context switch into a separate post-processor.

The trade in one line

CST is the workshop with every tool. RayRF is the sharp tool for the job most PCB RF designers actually do, at roughly a tenth of the cost.

Cost and trial

RayRF is 29 USD per month for the non-commercial Hobby tier and 149 USD per month, or 1,499 USD per year, for commercial use. There is a 30-day free trial with no card required, and a one-time founding-member option for early users. You can evaluate it on your own design the same day, without a sales call. See pricing for the full breakdown.

Accuracy and speed, honestly

We do not publish benchmarks against CST because the license forbids it. What we can show is RayRF against measured hardware on the validation page, and against openEMS on a matched mesh in the benchmark post. If you are weighing RayRF against the free option, the openEMS comparison is the one to read.

Frequently asked questions

Is there a cheaper alternative to CST Studio Suite for PCB work?

RayRF is a GPU FDTD simulator for planar PCB RF at 1,499 USD per year for commercial use, with a 30-day free trial. Published third-party figures put CST in the 14,500 to 22,000 USD per year lease range. RayRF is far narrower in scope but handles most PCB antenna, filter, and line work.

CST has a time-domain solver too. How is RayRF different?

CST time domain uses the finite integration technique, which is closely related to FDTD. The difference is scope and workflow, not just the method. CST is a broad 3D suite. RayRF is a focused planar PCB tool with a GPU solver, a single quality preset, and live results, at a small fraction of the cost.

Why no head-to-head benchmark against CST?

The CST license forbids publishing comparative benchmarks of the software. We respect that. We benchmark against openEMS instead and validate RayRF against physical VNA measurements.

Try RayRF on your own design

Draw a board, slide the quality preset, and click Run. 30-day free trial, no card required. Windows and Linux.

Start the free trial

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