Overview
Analysis
Solutions
Complete
·Feb 3, 2026
The Core Insight

The industry has been solving the wrong optimization problem

  • Consumer WPT adopted transformer design philosophy: maximize coupling coefficient at the design point.
  • But transformers have fixed geometry—the coupling doesn't change during operation.
  • WPT with position uncertainty should instead minimize coupling VARIANCE across the operating envelope.
  • Accept 87% at center to maintain 85% at edges, rather than 92% at center collapsing to 65% at edges.
  • EV charging figured this out; consumer products didn't because the communities don't overlap.
Viability
Solvable
  • Multiple proven solutions exist in adjacent industries; your constraints are actually less demanding than what EV and medical systems already achieve.
Key Decision

If you prioritize speed and certainty, pursue DD + Litz immediately—proven at scale, just needs geometry validation. If you're optimizing for competitive differentiation and can invest 8-12 weeks in R&D, the inverse-design approach could yield a fundamentally simpler architecture.

Solution Paths
01NEEDS VALIDATION

DD Coils + High-Strand Litz Stack

Proven EV charging topology + premium receiver wire; blocked only by FEM validation of DD fit in 50mm constraint

02NEEDS VALIDATION

MRI Inverse-Designed Flat-Response Coil

Compute coil geometry for minimum coupling variance instead of maximum coupling; blocked by AC extension of quasi-static methodology

Recommendation
  1. If this were my project, I'd start two parallel workstreams this week.
  2. First, I'd order 500-strand Litz wire samples from New England Wire—10m for $30-50, wind 5 test coils, measure Q-factor.
  3. This takes 2 weeks and $500-1,000 total.
  4. It's the lowest-risk way to establish a performance baseline and confirm whether high-strand wire delivers the theoretical Q improvement.
  5. Second, I'd run FEM simulation of DD geometry constrained to 50mm circular receiver.
  6. This is the blocking question for the primary approach.
  7. If DD achieves <2.5:1 k-variance, we have our answer—combine it with the validated high-strand Litz receiver and move to prototype.
  8. If DD shows >3:1 variance (only marginal improvement), I'd pivot to bipolar or invest in the MRI inverse-design approach.
  9. The mechanical centering concept intrigues me because it's orthogonal to everything else.
  10. If users accept a slightly tilting surface, it transforms the problem—standard Qi achieves your spec when centered within ±3mm.
  11. I'd build a quick prototype ($500 in ball joints and springs) and test it with 20 people before investing heavily in electronic solutions.
  12. If 70%+ like it, mechanical centering becomes the primary simplification strategy and all the electronic tolerance work becomes belt-and-suspenders rather than critical path.
  13. What I wouldn't do is jump to the complex adaptive multi-coil system.
  14. That's a 6-month, $100K development for a premium solution when simpler approaches haven't been tried.
  15. Save that for premium product tiers after validating that DD + Litz doesn't meet the spec alone.

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