RF Connectors Guide: 7 Key Things You Should Know

RF connectors guide transfer radio frequency signals. The link transmission cables to different applications, and you can also call them coax connectors. These connectors integrate well with coaxial cables, and you will find them mainly in television receivers, 2-way radios, Wi-Fi gadgets, and scientific tools.   

Cloom Tech customizes and manufactures various connectors. Our products have small components and modern designs. In addition, they have a complex assembly, minimizing losses and reflections. We combine local design and quality with international connector production capacities. This RF connectors guide discusses the seven key things about these connectors you should know.

1. RF Connectors Guide—RF Connector Definition

An RF connector Is an electrical linker that uses radio frequencies. As mentioned earlier, you can use these connectors with coaxial wires to maintain any coaxial design shielding effect. Remember, as frequency rises, the conduction cable impacts become essential. Minor connector impedance differences can reflect the signal instead of transmitting it. Therefore, a suitable RF connector should prevent external signals from entering the circuit.   

Mechanically, these devices may generate a fastening impact under minimal ohmic connections. Consequently, the effect facilitates excellent mating cycles and minimizes the insertion force. The last two decades have experienced an increase in RF circuit design research, and this is because of the high market demand for low-cost, high-data-rate connectors.   

2. The Primary RF Connector Specifications

Like most products, RF connectors contain multiple specifications for optimum performance. Most of the standard specifications for common devices also apply in RF connectors. However, manufacturers may express them in various ways to show multiple use cases. Let us have a look at the primary RF connector specifications. 

2.1 Connector Impedance Specifications

When you use connectors for RF purposes, they become part of the feed system. Since the feeder contains a known impedance, your connector should also include a specific impedance. Some connectors, such as the UHF connectors, have irregular impedance connections, and that is why you should use them for minimal frequencies only. However, most connectors, like the N-Type, SMA, and others, have a typical impedance.

2.2 Power Handling

In most use cases, a device’s power handling capacity is a minor factor. Nevertheless, it is a weighty aspect of transmitter gadgets. An RF connector’s central pin and mating vessel influence its power handling ability. Its inner part is smaller than the outer part, and this causes a high current density. Thus, the pin design and mating depot are essential to the connector signal specification.    

For optimum performance, you should align the pin and mating depot appropriately. Furthermore, you must ensure that there is no damage or dust between them. Again, it would be best if you plated the mating halves to achieve the correct connector specification. 

2.3 Plating/finish

Plating affects connector performance more than other manufacturing specifications, and this is because of the skin impact. Remember, an increase in frequency causes an increase in skin effect. The magnetic inductance from power transmission shifts power to the transmitter surface.   

The resistance from the transmitters causes heat loss. Furthermore, as the frequency rises, the cross-sectional area of the current decreases, and ultimately, the ohmic losses increase. 

At 1000 MHz, a copper transmitter contains a skin depth of about 2µm, and gold and silver have skin depths of 2.4µm and 2.0µm, respectively. On the other hand, Nickel displays a skin depth of 0.17µm because of its magnetic properties. Nickel’s low skin depth value makes it the most inferior microwave conductor, and its skin depth remains the same, even at 10 MHz. On top of that, it has the highest resistivity among the above metals, making Nickel a poor connector plating material.   

2.4 Coax Cable Compatibility

You can integrate most coaxial connectors with specific cables, and this is because they come in various sizes and dimensions. Therefore, you must design your coaxial connectors according to your line for proper integration. 

Typically, coax cable compatibility is not a big issue. This is because most manufacturers make connectors according to the standard coaxes. Hence, the primary coax connector specification is the cable type. Generally, you will be unable to integrate the coax to the connector when there is a significant inconsistency between them.

2.5 Voltage

The fifth RF connector requirement is the voltage capacity. Sometimes, the connector experiences high voltage levels. For example, there are more voltage levels at high current levels, and high levels of reflected power cause more voltages.  

2.6 Frequency Range

Different connectors conduct different frequencies. For example, BNC connectors work even at higher frequencies compared to UHF connectors. Still, some BNC connectors have slight differences. Some contain higher specifications and can function even at 10 GHz. But others cannot work well at 1 GHz. Therefore, if you are looking for connectors, purchase from reputable manufacturers. Cloom Tech customizes and manufactures high-quality products at cost-effective prices.

If you are sourcing from an open market, consider the quality and cost. Remember, most low-cost connectors are basically cheap but cannot function effectively. Thus, look at the specification carefully to determine its efficiency. For instance, not all N-type connectors perform above 18 GHz, only those designed to that description. 

2.7 Straight and Right-angled

A device’s mechanics determine the type of connector to use. However, you can use right-angled connectors in components of gadgets. The route away from the coax wire from the component assembly without the use of a loop. Consequently, they minimize the space you need to make connections.

Nevertheless, they often have a considerably lower specification. In most circumstances, this is a slight issue. But for high frequencies, it is a significant matter.

3. RF Connector Types

SMA Connectors

These are some of the most common types of RF connectors. Typically, they have a screw-like mating feature.

Apart from the male and female SMA connectors, we also have reverse thread and reverse polarity SMA connectors. 

SMB Connectors

They are smaller in size compared to their SMA counterparts.

Their distinguishing feature is a Snap-on coupling mechanism that facilitates quick connections.

Examples include the SMB male and female connectors.

FME Connectors

Engineers mostly use them with RG58, RG174, and other similar coaxial wires in mobile use cases.

They include the FME male and female connectors.

BNC Connectors

They are common in radio, TV, and other RF electronic gadgets. BNC connectors have a rapid-fix mating apparatus.

Besides the BNC male and female connectors, we also have male and female reverse polarity BNC connectors.

TNC Connectors

These are the threaded form of the BNC connectors. You can use them mostly in open-air tools because they are highly resistant to water.

Examples include the TNC male and female connectors and the reverse polarity male and female TNC connectors. 

N-Type Connectors

These are threaded radio frequency connectors. You can also use them in open-air tools since they are highly resistant to water.

They include the N-Type male, N-type female, reverse polarity N-Type male, and reverse polarity N-Type female.

MCX Connectors

They are smaller than MMCX connectors, and you can use them to link exterior antennas to GPS receivers.

They include the male and female MCX connectors.

MMCX

MMCX has a lock-snap feature that is stable and durable. They allow rotations of 3600, minimizing RF leakages.

The typical examples are the male and female MMCX connectors.

U.FL/IPEX Connectors

They closely resemble the IPEX MHF connectors. There are two types: male and female U.FL/IPEX connectors.

4. RF Connector Threading

On a coaxial wire, you will mostly find the thread on the exterior part. Still, you can find it on the interior of the connector. You can use these two words for each of these cases:

A female/jack connector

A male/plug connector.

5. The Center Pin

The component transmits the RF current. You can use the center pin to different connectors, and the center pin has two options, the standard and reverses polarities.

6. How to Define the RF Connector Gender and Polarity

To tell the gender and polarity of your connectors, consider these points:

First, ensure the plug and jack share the same polarity during mating. For instance, they can be RPSMA. 

Secondly, classify all the RF plugs as males. Also, the threads are on the inner part of the shell. 

Thirdly, classify all the RF jacks as females. Additionally, their threads are on the interior side. 

Lastly, the male shell seals the female body.

In addition to the above facts, here are some more valuable points:

A regular polarity male plug contains a central pin projecting from the middle. Besides, the plug comprises internal threads. 

A typical polarity female jack contains a socket at the center, and this is where the male plug pin fits during mating. Apart from that, the jack has external threads. 

A reverse polarity male plug contains a socket in the center, and this is where the pin of the female connector fits into during mating. 

On the other hand, a reverse polarity female jack contains a central pin. Additionally, the jack’s shells have external threads. 

By following the above rules, you will define the polarity and gender of your connector correctly.

7. How to Choose RF Connector Variations

After choosing the connector you will use, you also need to select the variations of your application. Between a plug and a jack, which one do you need? Do you need a straight or right-angled connector? The specific requirements of your use should guide your selection. 

Many use cases integrate well with straight connectors. However, you can go for a right-angled connector if you have limited space. It is important to note that right-angled connectors experience more signal loss than straight connectors. 

Conclusion

As discussed in this guide, there are multiple connector specifications. Some are standard specifications, while others are specific to individual applications. Having a good understanding of these specifications is helpful when choosing the appropriate connector for a particular application.

Are you creating a custom connector or seeking professional services? We trust this RF connectors guide has given you all the necessary information you need to get started. The manual has covered all the standard connectors. However, there are other minor variations we did not discuss in this article.

Are you searching for a reputable company to handle your connector needs? Contact us today for a free online quote.