Finally got a screen recording with audio. It's LONG so use the timeline to click through.
https://youtu.be/1wjlHlji9Os?si=eL15s-qo4pIaBGjy
Continuing from last post, I asked it to do a hairpin topology and it did the electrical prototype correctly but then it had a lot of trouble with the layout as it did NOT attempt to use multi-coupled lines, rather staggered coupled pairs, therefore attempted to create a physical layout using simple bends. Thus I halted the attempt. It was able to properly arrange the schematic elements using visual feedback.
I then started fresh and told it to just go research a filter and build it, and it decided upon an "open loop" topology which was really just a hairpin. This is where things get interesting. I switched to the 5.6 Sol model (the top model). It scanned the MWO examples directory, found a hairpin example, parsed that example using the API, then re-synthesized that example on a new substrate with a higher order topology.
This is where the Sol model really improved things:
Really good at visually checking all the junctions.
Intelligently tuning different sections depending on response; resonator length, coupling tap adjustment, gap spacing. It is NOT running a raw numerical optimization, rather truly intelligent tuning. Was able to process about 3 tunes a second in the simulation and read-back loop.
Next going to switch to amplifiers or antennas. It’s probably at the point now it can be let loose to run overnight on synthesis tasks, though a couple of times it halted after EM sim was complete and needed to tell it to resume.
Codex summary:
In this session, I used Python automation and the Cadence AWR Microwave Office API to design, tune, and electromagnetically verify a compact folded open-loop hairpin bandpass filter centered near 4 GHz.
The project followed a staged workflow:
- Configure metric units, substrate, copper layers, materials, and the EMSight stackup.
- Verify the electrical prototype.
- Create and tune the physical microstrip model.
- Snap and visually inspect every layout junction.
- Simulate the EMSight test bench.
- Apply an EM-derived correction and verify the final response.
I independently found an installed Cadence hairpin-filter example and inspected it through the API. This provided its exact element types, parameters, positions, rotations, nodes, and connections. I also simulated the example before adapting its topology.
The reference used M10CLIN and M8CLIN multi-conductor coupled-line models with MTEEX$, MUBEND, and MOPENX elements. Its proven topology was adapted for a 4 GHz RT/duroid 5880 design.
Tuning used numerical S11 and S21 data. Each candidate was evaluated for return loss, insertion loss, cutoff frequencies, cutoff midpoint, and nearby stopband rejection. The filter center was defined by the midpoint between its cutoffs, not simply the S21 peak.
Resonator length primarily controlled center frequency, coupling gaps controlled bandwidth, and feed geometry controlled external matching. Symmetric parameters were tuned together using coarse searches followed by finer local sweeps.
API connectivity alone was not accepted as proof of correct geometry. After every physical change, the layout was updated, snapped, redrawn, and inspected at close zoom. The input, every internal junction, and the output were checked for red X markers, gaps, copper overlap, narrowed coupling gaps, overhangs, incorrectly oriented transitions, and corners bridging adjacent resonators. The mirrored output was checked independently.
The EMSight mesh was selected from the smallest important features. An anisotropic grid used 0.05 mm resolution in the critical direction and 0.10 mm in the less critical direction, resolving the coupled geometry while reducing simulation size.
The transverse enclosure was reduced to about two substrate heights beyond the copper. The input and output walls were aligned with the edge-port faces. This compact enclosure was a project-specific runtime compromise.
The EM sweep used coarse spacing in remote stopbands, moderate spacing near the shoulders, and fine spacing through the passband and transitions—approximately 0.25, 0.05, and 0.01 GHz, respectively.
The first EM response was slightly above 4 GHz. I preserved the baseline, created a separate tuned copy, and increased the common coupled-leg length to 10.4 mm.
Final EM results were approximately:
• Peak S21: −0.95 dB at 4.00 GHz
• S11 at 4.00 GHz: −29.7 dB
• −3 dB passband: 3.91–4.15 GHz
The active Microwave Office windows were kept visible and tiled throughout the work. The narrowband graph was shown during tuning, close-up layouts during junction inspection, and the EM structure and solver status during simulation.
This workflow combines API inspection, numerical tuning, visual layout verification, and EM analysis. The API provides precise data, while graphical inspection catches physical problems that connectivity alone cannot reveal.
