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ABOUT US
Two engineers keeping notes on one narrow corner of RF, because nobody else bothered.
01 / Who we are
It started because the answer took three days to find.
Green Button was a shared text file in 2009, passed back and forth between two RF engineers who kept burning afternoons on one question: will this plug mate with that receptacle, and what does the joint cost me once it does? The information existed the whole time. It sat scattered across fourteen PDFs that never referenced each other.
Seventeen years on, that text file turned into this site. It covers the smallest end of RF interconnect: MMCX, MCX, U.FL / IPEX, MHF, SMA, SMB, SMP and the ultra-miniature trademarks orbiting them. Three plain questions per interface. What is it. What does it do when you put it on a bench. What will it mate with.
We sell no connectors, no cable, no adapters, no assemblies, and we take no manufacturer money. A constraint we chose, not a brag. It buys exactly one thing: a page here can state that a heavily marketed cross-reference falls apart above 6 GHz, and nothing happens to us.
02 / Editorial principles
Four rules we do not bend.
Label the provenance of every number
A figure came off a published manufacturer spec, or it came off our bench. The page says which. Ours arrive with the method and the sample size attached.
Quote worst case, not best sample
Means flatter. Where we hold the spread, we print the spread, because volume production lives out in the tail of the distribution and never in the comfortable middle.
No sponsorship, no affiliate links
Nothing here is paid placement, and no manufacturer reads a page before it goes up. We name trademarks because precision demands names.
Say when we do not know
Some pairings have never crossed our bench. Some vendor specs contradict each other flat out. Those get marked open, rather than papered over with a number that reads well.
03 / Methodology
How the measured figures get made.
When this reference prints its own data instead of citing a datasheet, here is the setup behind it.
| Step | Method | Range | Notes |
|---|---|---|---|
| Sample preparation | Single reel, single operator, one session | 0.81–3.0 mm OD | Removes lot and operator variation |
| Fixture calibration | SOLT, verified against a known standard | 300 kHz–20 GHz | Re-verified every fifth sample |
| Insertion loss | 2-port VNA sweep | DC–18 GHz | Reported at 2.4 / 5.8 / 6 / 8 GHz |
| Return loss / VSWR | Same sweep, S11 and S22 | DC–18 GHz | Worst port reported |
| Retention force | Digital force gauge, axial | 0–250 N | Ten samples minimum |
| Thermal behaviour | Cycled chamber, swept at intervals | −55 °C to +125 °C | Swept every 200 cycles |
| Sample size | Stated on every published figure | Typically 10–40 | Never a single specimen |
Raw touchstone files behind published comparisons are available on request — see contact.
04 / History
Seventeen years, one subject.
The reference grew one unanswered question at a time. Nearly every section exists because somebody asked twice.
- 2009
A shared text file
Two engineers start writing down which ultra-miniature plugs really mate, after a third afternoon vanished into the question.
- 2013
First measured comparison
Swept data replaces quoted datasheet figures wherever the two disagree. Our method page dates from here.
- 2016
The cross-reference table
Ultra-miniature trademarks mapped and graded interchangeable, conditional or do-not-mix. Still the most-read page we have.
- 2019
Adapter loss matrix
Between-series transitions swept and tabulated, after a decade of hearing that adapters cost nothing.
- 2022
MHF 4 and 4L added
Low-profile coverage pushed out to 15 GHz once sub-1.5 mm stack heights stopped counting as exotic.
- 2026
Seventeen interfaces documented
Glossary, standards index and comparison tables folded into the reference you are reading now.
06 / Scope & limits
What this reference is not.
Not a shop
Nothing is for sale. No part numbers, no pricing, no stock, no quotes.
Not a standard
Where a published standard exists, we point at it. Nothing here stands in for the specification itself.
Not affiliated
No manufacturer sponsors, reviews or funds this site. Trademarks named here belong to their owners.
Not finished
Interfaces change and pages go stale. Every table is revised when needed.