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What are the relative merits of using a Type-N connector vs an SMA connector for an RF application up to \$18\,\text{GHz}\$? From the type-N wikipedia page (linked), it's stated that the type-N connector is favored when ruggedness is required. What does this mean specifically? In comparison with an SMA connector, does this mean that the type-N connector has a higher rated number of mating cycles? Some of my additional guesses are that it's more difficult to bend the inner conductor pin of a type-N and that the dielectric between the inner and outer conductors is less exposed to scratching during mating than the SMA connector. An additional advantage of type-N connectors is that they are meant to be hand-tightened, whereas SMA connectors should be tightened with a torque wrench to achieve the best performance.

The main advantage of the SMA connector seems to be size, since it's quite a bit smaller. This means that it's easier and cheaper to mount to a PCB (requires less board space) and (as far as I can tell) there are a lot more options for SMA PCB connectors than for type-N. Is there an additional performance benefit to SMA connectors? Some manufacturers offer SMA connectors good up to \$26.5\,\text{GHz}\$, whereas I haven't seen the same for type-N connectors. Additionally, the higher performance connectors (3.5mm, 2.92mm, etc.) look a bit like SMA connectors (and indeed some can be mated with SMA). Does this mean that it's easier to achieve better performance (e.g., lower VSWR) with the structure of an SMA connector?

Are there any other advantages/disadvantages to each that I haven't mentioned? Are my guesses correct?

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You already worked out for yourself some of the important differences.

One that you missed is power handling. The N-type connector can typically handle about 3x the signal power of the SMA without overheating:

enter image description here

(Image source: Southwest Microwave)

The peak power capability (governed by the dielectric breakdown limit) is similarly higher for N-type compared to SMA, due to the greater distance between inner and outer conductors. For example, Amphenol rates their SMA connectors for 1000 V rms (source) and their N-type connectors for 1500 V (source).

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From the type-N wikipedia page (linked), it's stated that the type-N connector is favored when ruggedness is required. What does this mean specifically?

Type N is about 10 times larger than SMA this means it's harder to break.

does this mean that the type-N connector has a higher rated number of mating cycles?

That would be "durability" not "ruggedness"

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    \$\begingroup\$ So, durability means resistance to wear (i.e., continual use) and ruggedness means resistance to one-off breaks? \$\endgroup\$
    – MattHusz
    Commented Oct 22, 2020 at 3:33
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    \$\begingroup\$ @MattHusz I would actually call number of cycles endurance rather than durability, but whatever it is, it is certainly not ruggednness. That said, I think the article actually does mean ruggedness (ability to survive harsh environments and handling) and not number of cycles. Durable is rather catch-all and can mean whatever you want it to mean. \$\endgroup\$
    – DKNguyen
    Commented Oct 22, 2020 at 5:05

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