CapExt is a capacitance simulator designed specifically for electronic circuit boards, with the philosophy that it should be easy to use, while still providing accurate results. Simulate the self-capacitance of a single electrode, and its capacitive coupling to other electrodes, using a physically accurate 3D Monte Carlo method.
Using CapExt is easy, the only input needed, in addition to the Gerber-files themselves, is the thickness and material (e.g. glass, FR4 etc.) of each layer. The electrodes are automatically extracted from the provided RS-274X Gerber-files, taking into account vias connecting the layers. Select which electrodes you are interested in simulating the capacitance for, and run the simulation.
View the self-capacitance for each selected electrode, or dig down to examine the mutual capacitances. All electrodes contribute to the mutual capacitance, not just the electrodes selected for simulation. An estimate of the error is also provided, and if more accurate results are needed, simply let the simulation run for a longer period of time.
CapExt supports the industry standard RS-274X Gerber format. It can also import common picture formats like .bmp and .png.
CapExt is optimized for PCBs and similar planar designs. Results are available within minutes on a typical work-station. If higher accuracy is needed, simply let the simulation run for more iterations.
It is easy to modify the stackup, to include for example a glass or plastic overlay over the PCB, or increase or decrease the layer thickness.
Use the integrated 3D view to quickly identify the physical electrodes. Click any electrode in the 3D view to find the corresponding electrical net in either the simulation options pane or the simulation results pane. Hover over any simulation result to highlight the corresponding electrode in the 3D view.
Include the whole system in the simulation, including the entire PCB with all conductive traces, any overlays and metal planes.
With a CapExt, the exact capacitive coupling between two lines is easily extracted. Measure and reduce unwanted capacitive coupling before you send your Gerbers to production.
Account for trace capacitances when choosing balancing capacitors for crystal oscillators, when fine-tuning analog filters or when designing digital communication lines for fast transmission-rates.
Both ITO-based sensors and copper electrodes can be simulated, for both self- and mutual capacitance.
Optimize sensors to ensure that the parasitic capacitance is low enough to ensure fast measurements, while keeping the sensor sensitive to touches. Since there is no limitation on the number of electrodes present in the simulation, you can simulate a whole large touchscreen with hundreds of sensitive electrodes, capturing not only the capacitive coupling between each electrode, but also the capacitive effects due to the stackup above and below the sensor.
For wearables or other small PCBs, the capacitance between lines on nearby layers are usually quite high due to the thinner PCB substrates used. By using an accurate capacitance simulator, it is easier to achieve optimal routing, with less of a risk than when using rules of thumbs to estimate capacitances.
|Operating System||Windows 7 or newer (for Linux and OS X builds, please email firstname.lastname@example.org)|
|CPU||32-bit or 64-bit Intel® or AMD® processor (64 bit recommended)|
|RAM||1 GB of RAM (4GB recommended)|
|Disk Space||100 MB free disk space for install|