E&M Reality Emerges with Robert Fennis

Robert Fennis is an RF engineer and consultant from the Netherlands and the creator of EMerge: a free, open-source 3D Finite Element Method (FEM) electromagnetic solver written in Python . He joins Chris to discuss demystifying the black magic of RF engineering, the mathematical and physics foundations of simulation, and how Emerge is “the IKEA of FEM solvers” in that it makes electromagnetic simulation accessible to everyone. Timeline Chris welcomes Robert Fennis , creator of EMerge, to discuss RF simulation as a way to unlock knowledge of the universe. (00:00:15) LinkedIn Shout-outs: Chris and Robert praise the amazing RF visualizations done by past guests Lukas Henkel , Sam Aldahar , and Katerina Galitskaya . (00:01:20) The Wizard School of RF: They discuss how RF engineering is often seen as a black magic wizard school of electronics, despite being normal to Robert. (00:03:10) Pyramid of Knowledge: Robert explains how learning RF and simulation is like building a pyramid step-by-step, where you have to understand waves, ports, and S-parameters rather than trying to build it all from scratch. (00:05:00) Python and LLMs: EMerge is written as a Python module but utilizes fast external libraries under the hood. They talk about how script-based engineering allows LLMs to assist by writing simulation code from existing examples on the EMerge Hub on GitHub . They draw a comparison to OpenSCAD’s parametric code-first approach in mechanical design. (00:07:30) The Big Three Full-Wave Simulation Methods: Robert explains how full-wave solvers attempt to approach exact solutions to Maxwell’s equations. (00:11:30) Finite Difference Time Domain (FDTD): A time-stepping method that operates similarly to movie physics engines, marching forward in time. (00:12:15) Method of Moments (MoM): A method solving specifically for currents and voltages on conductors, using Green’s functions to calculate interactions without discretizing the surrounding air. (00:13:40) Finite Element Method (FEM): A frequency-domain solver derived from variational calculus (the Principle of Least Action). It solves for complex electric fields in the airspace surrounding conductors, treating conductors as boundary constraints. (00:15:10) The Veritasium Switch Video: They connect the physics of FEM to the famous Veritasium switch debate, noting that energy travels outside of wires. This is why FEM solvers must discretize the surrounding airspace to capture the physics, as famously illustrated in the Veritasium switch video . (00:18:20) The Challenges of Real-World Boundaries: In FEM, boundary conditions define where the simulation ends. Choosing the right boundaries is critical because perfect electric conductors can introduce unrealistic internal resonances. (00:20:45) Simplifying vs. Overcomplicating Models: Mentor advice on simplifying models to ensure convergence. Robert warns that adding too much detail quickly exhausts RAM, which is currently expensive. (00:22:15) Frequency and Detail: A rule of thumb is that higher frequencies make small details matter more. Right-angled corners on PCB traces act as parasitic capacitors at 10 GHz, and silk screen on a 2.4 GHz patch antenna can completely de-tune it. (00:24:30) Bluetooth Antenna Design Workflow: Chris shares his fear of designing custom 2.4 GHz antennas for boards like the NRF52840. Robert outlin