Description
What is an SMA connector?
SMA connectors are semi-precision coaxial RF connectors developed in the 1960s as a minimal connector interface for coaxial cable with a screw-type coupling mechanism. The connector has a 50 Ω impedance.
SMA connector is a widely used semi-precision ultra-small RF and microwave connector, especially suitable for RF connections in electronic systems with frequencies up to 12 GHz or higher.
SMA connectors come in many forms, male, female, straight, right-angle, partition fittings, etc., so that they can meet most requirements. Its ultra-small size also allows it to be used, even in relatively small electronic devices.
Although it is very mature now, the use of SMA connectors may expand because many new RF systems see their operating frequencies extend well into the microwave region.
SMA connector on PCB
Although the SMA connector looks very similar to the standard household connector used for home satellite TV and other similar applications. These household connectors are called F-type coaxial connectors, and they have 75Ω impedance.
They have different diameters and cannot be mated with SMA connectors-they require a special adapter, and then there will be an impedance mismatch.
Basic knowledge of SMA connector
The SMA connector is a subminiature coaxial cable connector whose name comes from the Sub-M iniature A connector. It has found many applications to provide connections for RF components in devices that require coaxial connections.
It is commonly used to provide RF connections between circuit boards. Many microwave components include filters, attenuators, mixers, and oscillators, using SMA connectors.
The connector has a threaded external connection interface, which has a hexagonal shape and allows tightening with a wrench. A special torque wrench can be used to tighten them to the correct tightness so that a good connection can be achieved without over-tightening. The required torque is usually 8-inch pounds.
Right-angle male SMA connector
The SMA coaxial RF connector was originally designed by Bendix Scintilla Corporation and Omni-Spectra Corporation in the 1960s. The first SMA connector is designed for 141 semi-rigid coaxial cables.
The original SMA connector can be called the smallest connector because the center of the coaxial cable forms the center pin of the connection, and there is no need to transition between the coaxial center conductor and the center pin of the special connector.
It also has the advantage that the cable dielectric is directly connected to the interface without an air gap. The disadvantage of the connector is that it can only perform a limited number of connection/disconnection cycles.
However, for applications using semi-rigid coaxial cables, this is unlikely to be a problem because the installation is usually fixed after the initial assembly.
However, its use was extended to other flexible cables, and a full connector with a center pin was introduced. These connectors are manufactured to high standards and also allow a greater number of connecting/disconnect cycles to be performed.
SMA connector performance
The SMA connector is designed to have a constant, 50-ohm impedance on the connector. SMA connectors were originally designed and designated for work up to 18 GHz, although some versions have a top frequency of 12.4 GHz and some versions are designated as 24 or 26.5 GHz. Higher upper-frequency limits may require operation with higher return loss.
The actual specifications of a given connector largely depend on the manufacturer and type-several different quality/performance levels are available. It is better to check the connector specifications carefully
Generally, SMA connectors have a higher reflection coefficient than other connectors up to 24 GHz. This is due to the difficulty of accurately fixing the dielectric support, but despite this difficulty, some manufacturers have managed to appropriately overcome this problem and can specify their connectors for 26.5GHz operation.
For flexible cables, the frequency limit is usually determined by the cable rather than the connector. This is because the cables accepted by SMA connectors are very small, and their loss is naturally much greater than the loss of the connector, especially at the frequencies at which they may be used.
Rated power of SMA connector
In some cases, the power rating of the SMA connector may be important. The key parameter that determines the average power handling capability of a coaxial connector is its ability to deliver high currents and keep the heat up to a moderate temperature.
The heating effect is mainly caused by the contact resistance, which is a function of the contact surface area and the way the contact pads are together. One critical area is the center contact contacts must be formed correctly and fit together well. It should also be noted that the average power rating decreases with frequency because resistive losses increase with frequency.
The power handling data of SMA connectors vary greatly between manufacturers, but some figures indicate that some can handle 500 watts at 1 GHz, which drops to slightly less than 200 watts at 10 GHz, but this is much higher than many people have Faith passes through them.
SMA Male Coaxial Cable Connector Specifications:
| Item NO.: CTRF-CN-SMA-Male
Key Specifications of the SMA Male Coaxial Cable Connector |
|
| Connector Series | SMA |
| Connector Gender | Male |
| Connector Polarity | Standard |
| Connector Angle | Straight |
| Connector Mount Method | None |
| Connector Impedance | 50Ohms |
| Frequency | DC 0-12Ghz |
| V.S.W.R | ≤1.3 |
| Voltage Breakdown | DC1000V/50Hz |
| Insertion Loss | ≤0.1dB/GHz |
| Insulation Resistance | ≥5000MΩ |
| Contact Resistance | Shell≤2mΩ; Center Pin≤3mΩ |
| Center Pin Retention | ≥50g |
| Mating Cycles | >500 |
| Operation Temperature | -40℃~+65℃ |
| Storage Temperature | -40℃~+80℃ |
| Junction Retention | ≥8KG |
| Color | Golden |
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SMA Connectors/ Adaptors / Jacks / Plugs
SMA series is a popular general-purpose high-performance 50-ohm connector. SMA has a screw-together coupling with versions available for use up to 12GHz and features gold-plated bodies and center contacts. SMA connectors are suited to a wide variety of industries from high-performance applications in defense and aerospace to general-purpose industries.
Reverse polarity versions are also available.
The SMA connector product line for coax, PCB, and terminal is available with various clamp/solder, crimp/crimp, crimp/solder, field replaceable, solder, solder (without contact), solder/non-solder contact, and solder/solder attachment methods.
SMA connector compatible cable types include: .020 SR, .034 SR, .047 SR, .086, Harbour LL142, Harbour LL335, LMR-100, LMR-195, LMR-200, LMR-240, LMR-240-UF, LMR-400, M17/152-00001, PE-C100, PE-C195, RG141, RG142, RG174, RG188, RG223, RG303, RG316, RG316DS, RG402, RG405, RG-405, RG55, RG58, RG8X.
Other RF connector options include .040 end launch, .042 end launch, .044 end launch, .047 end launch, .052 end launch, .056 end launch, .062 end launch, edge mount .005 pin, edge mount .007 pin, edge mount .010 pin, pin, slotted contact, solder cup, stub, surface mount, tab, and thru-hole.
LMR® is a registered trademark of Times Microwave
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