SMA (SubMiniature adaptation A) connectors are coaxial RF connectors developed in the 1960s as a basal adapter interface for coaxial cable with a spiral blazon coupling mechanism. The adapter has a 50 Ω impedance. It offers accomplished electrical achievement from DC to 17 GHz.
Monday, February 27, 2012
Connector design
The SMA adapter consists of a 1/4"-36 thread. The macho is able with a 0.312" (7.925 mm) hex nut.
In SMA and RP-SMA connectors, the agreement "male" and "female" accredit alone to the macho centermost pin and its changeable sleeve analogue rather than to the accoutrement that are acclimated to authority the affiliation in place. The macho adapter has central accoutrement while the changeable adapter has alfresco threads.
The SMA adapter uses a polytetrafluoroethylene (PTFE) dielectric which will acquaintance forth the alliance plane. Variability in the architecture and the alliance of the connectors absolute the repeatability of the adapter impedance. For that reason, an SMA adapter is not a acceptable best for metrological applications.
SMA connectors are rated for 500 alliance cycles, but to accomplish this it is all-important to appropriately torque the adapter if authoritative the connection. A 5/16 inch torque bend is appropriate for this, set to 3–5 in·lbf (0.3 to 0.6 N·m) for brass, and 7–10 in·lbf (0.8 to 1.1 N·m) for stainless animate connectors. Flats are sometimes aswell provided on the cable ancillary of the adapter accumulation so that a additional bend can be acclimated to anticipate it from alternating and damaging the collective to the cable. It is aswell appropriate to apple-pie out apart bits from the centralized surfaces with aeroembolism air afore mating.
In SMA and RP-SMA connectors, the agreement "male" and "female" accredit alone to the macho centermost pin and its changeable sleeve analogue rather than to the accoutrement that are acclimated to authority the affiliation in place. The macho adapter has central accoutrement while the changeable adapter has alfresco threads.
The SMA adapter uses a polytetrafluoroethylene (PTFE) dielectric which will acquaintance forth the alliance plane. Variability in the architecture and the alliance of the connectors absolute the repeatability of the adapter impedance. For that reason, an SMA adapter is not a acceptable best for metrological applications.
SMA connectors are rated for 500 alliance cycles, but to accomplish this it is all-important to appropriately torque the adapter if authoritative the connection. A 5/16 inch torque bend is appropriate for this, set to 3–5 in·lbf (0.3 to 0.6 N·m) for brass, and 7–10 in·lbf (0.8 to 1.1 N·m) for stainless animate connectors. Flats are sometimes aswell provided on the cable ancillary of the adapter accumulation so that a additional bend can be acclimated to anticipate it from alternating and damaging the collective to the cable. It is aswell appropriate to apple-pie out apart bits from the centralized surfaces with aeroembolism air afore mating.
Variations
The SMA adapter is about rated for mode-free operation from DC to 18 GHz, admitting some proprietary versions are rated to 26.5 GHz. For achievement aloft this, SMA-like connectors are used. These are the 3.5 mm connector, rated to 34 GHz, and the 2.92 mm (also accepted as 2.9 mm, SMK, or K type),1 acceptable up to 46 GHz. These connectors accumulate the aforementioned alfresco cilia as the SMA, so they can all be cross-mated, about they use an air dielectric, with the centermost conductors appropriately scaled. However, the activity of the attention adapter will be reduced, and can be calmly damaged if alliance with low-grade SMA connectors.
Beyond 46 GHz, the 2.4 mm, 1.85 mm and the 1 mm adapter exist. These are agnate to the SMA connector, but with the geometries abnormally scaled. These accept mode-free operation to 50, 65, and 110 GHz respectively.
Beyond 46 GHz, the 2.4 mm, 1.85 mm and the 1 mm adapter exist. These are agnate to the SMA connector, but with the geometries abnormally scaled. These accept mode-free operation to 50, 65, and 110 GHz respectively.
Reverse polarity SMA
Reverse polarity SMA (RP-SMA or RSMA) is a aberration of the SMA adapter blueprint which reverses the gender of the interface, as apparent in Figures 1 and 2. The appellation "reverse polarity" actuality refers alone to the gender of the connector's acquaintance pin, not in any way to the arresting polarity.
Female RP-SMA adapter is one you will see on your PCI agenda or WiFi router, and the antenna affiliated to it has a macho RP-SMA connector.
Female RP-SMA adapter has alfresco accoutrement but has an close pin (hence reversed), and macho RP-SMA adapter has central accoutrement and pin aperture in the middle.
RP-SMA connectors were alien to abstracted able and commercially accessible equipment, preventing accidental or advised affiliation of high-gain able antennas with SMA adapter and bartering wireless accessories with RP-SMA connector, actionable federal or all-embracing laws. Today, however, both blazon of connectors are readily available.
The changeable RP-SMA adapter has the aforementioned alien apartment as a accepted or accepted changeable SMA connector, which consists of an alien carapace with the accoutrement on the outside; however, close changeable pin aperture is replaced by a macho pin. Similarly, the RP-SMA macho has accoutrement on the central like a accepted male, but has a changeable pin aperture instead of the macho pin in the middle.
Female RP-SMA adapter is one you will see on your PCI agenda or WiFi router, and the antenna affiliated to it has a macho RP-SMA connector.
Female RP-SMA adapter has alfresco accoutrement but has an close pin (hence reversed), and macho RP-SMA adapter has central accoutrement and pin aperture in the middle.
RP-SMA connectors were alien to abstracted able and commercially accessible equipment, preventing accidental or advised affiliation of high-gain able antennas with SMA adapter and bartering wireless accessories with RP-SMA connector, actionable federal or all-embracing laws. Today, however, both blazon of connectors are readily available.
The changeable RP-SMA adapter has the aforementioned alien apartment as a accepted or accepted changeable SMA connector, which consists of an alien carapace with the accoutrement on the outside; however, close changeable pin aperture is replaced by a macho pin. Similarly, the RP-SMA macho has accoutrement on the central like a accepted male, but has a changeable pin aperture instead of the macho pin in the middle.
Outside Thread
RP-SMA connectors are broadly acclimated by Wi-Fi accessories manufacturers to accede with specific bounded regulations {Section 15.203 Antenna requirement}, e.g., the FCC, which were advised to accomplish it difficult for consumers to affix antennas with accretion and thereby aperture compliance. However, RP-SMA able antennas are now broadly available.
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