RF Connectors Guide: 7 Key Things You Should Know - WIRINGO

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.   

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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 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 , 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. 

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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.

The connector world is constantly evolving to support dynamic market trends. Emerging high-speed connectivity products are currently responding to a number of technology trends and, once released to market, will serve, inspire, and enable a multitude of next-gen, high-speed applications for many years to come.

By Wayne Shockloss|December 15,

As businesses and consumers demand more convenience, mobility, power, and speed from the devices we use, design engineers require more from the connectivity solutions they employ to push these devices to the next level. More powerful, versatile, and innovative connectors are becoming available to serve these designs. Many factors are fueling the growth of the electronics industry, but the five key technology trends that follow will have an especially strong influence on new connector design and development in the years to come.

Technology Trend #1: High-speed connectivity solutions will support 5G networks and faster, ultra-high-bandwidth, lower latency signals.

As 5G networks continue to roll out, high-speed connectors and cables are needed to support this infrastructure and the substantially higher data rates it will carry. Powerful new technologies will be made possible by this instantaneous connectivity. Network equipment and remote radio and active antenna systems will bear the brunt of this activity. The promise of high-speed connectivity will have an especially profound impact on markets such as automotive, transportation, and test and measurement. The connector industry has been ahead of this demand, and several companies have already developed next-gen high-speed solutions.

Samtec’s co-extruded Eye Speed® ultra-low-skew twinax cable technology reduces the performance limitations and inconsistencies of individually extruded dielectric twinax cabling, with improved signal integrity, bandwidth, and reach for high-performance system architectures.

Samtec has a range of interconnect solutions that feature vertically integrated high-speed connectors combined with high-performance micro-coaxial cable. The company manufactures its own unique cable products at Samtec Cable in Wilsonville, Oregon.

Samtec’s Flyover® QSFP28 cable systems provide improved signal integrity and architectural flexibility by routing critical high-speed signals through low-loss, ultra–low–skew twinax cable, instead of through expensive, lossy PCBs. Their ultra-high-density design includes sideband signaling via press-fit contacts to help increase airflow, and a multitude of options allow for maximum design flexibility.

Samtec’s FireFly™ Micro Flyover System™ is an inside-the-box, mid-board optics interconnect solution with performance to 28Gb/s and a future path to 56Gb/s. It is designed to allow copper or fiber optics to use the same high-performance connector system.  

Technology Trend #2: Magnetic, LED, vibration, and combination user-recognition mating systems are changing the way connectors come together.

For many years, users have relied on tactile and audible mating cues to indicate positive connector engagement. Some of the latest interconnect solutions are taking this to a new level with magnetic, LED, or vibration features, or combinations of technologies designed to assure users that they have achieved a secure, properly mated coupling. This is especially critical in difficult-to-reach architectures and high-reliability applications including medical, military, and aerospace applications.

Rosenberger’s MultiMag Series connectors are designed for compact applications with high mating cycles and cable safety demands. These magnetic self-mating connectors provide a secure connection with little effort and safely breakaway if subjected to acute tensile force. Variants include MultiMag 15 (top) for general power and data transmission MultiMag 6 (bottom)for USB applications. 

Rosenberger’s MultiMag connectors feature a breakaway function designed to disconnect should the plug or cable be subjected to acute tensile force. This disconnection capability avoids the risk of injury to the user, as well as inadvertent device or connector damage. MultiMag connectors are ideal for environments and devices where frequent connection and disconnection are prerequisite, such as medical and industrial automation equipment. They are also ideal for drones, robots, smart watches, and smart eyewear.

LEMO’s HALO LED connectors have an LED–lighted flange that visually confirms connector mating engagement. HALO LED technology can be packaged within the LEMO’s B and T Series push-pull metal circular connectors. 

LEMO’s HALO connectors have an LED-illuminated flange that clearly displays the connection status, alerting users to connection issues or providing unmistakable visual confirmation of securely mated connectors. These connectors have a circular array of LEDs positioned on the connector flange. These LEDs are available in white, red, green, and blue to provide additional distinction in complex cable arrays, and design engineers can specify up to two different colors.

This Magnetic Medical Connector System from Onanon, an Amphenol company, features a magnetic pole that enables easy and intuitive mating and unmating, as well as LED-illuminated receptacles that shine red in the unmated condition and green in the mated condition and also vibrate when mated to provide visual, tactile, and audible confirmation of proper connections.  

Trends favoring portability, mobility, and wearable devices continue to influence every market. To make these compact designs possible, connector suppliers are delivering miniaturized form factors with higher contact densities. The latest generation of connectivity products conserves space and reduces weight without compromising functionality. This trend has fueled a boom in wearable devices, which has brought great flexibility and more user-friendly designs to medical, consumer, and military markets.

Omnetics Connector Corporation’s connectors and cable assemblies are known for their small size, light weight, durability, and reliability in tough environments. 

Omnetics Connector Corporation designs and manufactures standard, custom, and application-specific micro and nano connectors and cable assemblies for devices where miniaturization is desirable. Omnetics’ expertise lies in providing connectivity solutions for applications that operate in rigorous environmental conditions, such as mission-critical medical, industrial, military, defense, and aerospace applications. EMI shielding, IP sealing, polarization, and rugged materials in miniaturized package sizes serve designers working in these complex markets.

Mill-Max Mfg. Corp. is another company that delivers small, precise connectors for applications that need to conserve size and weight while delivering high levels of power and data. As military, aerospace, medical, and other high-reliability markets continue to scale down existing equipment and innovate new products, versatile connectors will be needed to make these designs possible.

Mill-Max offers four diverse, off-the-shelf Turned PCB Pin Sockets designed for fine-pitch applications that require miniature receptacles. Each receptacle contains three-finger beryllium copper contacts that range from 0.008” (0.2mm) to 0.013″ (0.33mm) in diameter and are suitable for use in high-density configurations down to a 1mm pitch. These contacts are also characterized by a low insertion force that makes them compatible with miniature leads subject to bending.  

Fischer Connectors and Wearin’, Fischer’s new spin-off, work collaboratively to design and develop wearable connectivity solutions for the connected human. Wearin’ vests are currently available in defense and industrial versions, both of which utilize Fischer’s small, lightweight connectivity solutions for IoT devices to integrate sensors, cameras, batteries, switches, hubs, and communication devices such as GPS and tactical computers into a functional garment. These vests can transmit and receive critical situational information and utilize AI data analysis to enhance the performance and safety of the person wearing it.

The Wearin’ Defense (left) and Wearin’ Industrial (right) vests helps keep soldiers, security personnel, and workers safe in military, defense, and industrial environments ranging from battlefields to factories. These hands-free garments serve as protective devices with the integration of sensors that collect data and deliver to the cloud for analysis.

Technology Trend #4: More than just power, wireless charging headwinds create adoption tailwinds.

Wireless power transfer is the transmission of electrical energy without traditional plug-and-play connectors and is designed to increase the mobility, convenience, and safety of electronic devices. Wireless charging has emerged as a popular feature for smartphones, earbuds, fitness bands, handheld computers, and other devices. It is also emerging for electric vehicles. Initially, designers were drawn to the convenience and interoperability that wireless charging can provide to users, but now engineers explore this technology with an eye towards eliminating some traditional mechanical connectors.

Near-field communication (NFC) is the newest entrant for wireless power standards, and its potential is massive. With an installed base of billions of devices, NFC has traditionally been used as a communications platform. However, the NFC Forum standards body turned on a small amount of power transfer (~0.5 watts received) as part of its protocol. This creates new opportunities for wireless charging in a variety of small, space-constrained devices. Some of the initial products rolling out with this method of wireless power transfer include Samsung’s Galaxy Fit and Huawei’s Gentle Monster smart glasses. For this technology to take off, the amount of power received will need to increase while keeping NFC data transfer rates in the 108–848Kb/s range.

“We’re seeing a number of applications where connectors are being eliminated as a result of adding wireless charging,” said Rob Diebold, global director of sales at NuCurrent, who previously served in a corporate venture role at Molex, where he made early investments in wireless power companies based on their disruptive potential. “NFC wireless charging introduces possibilities to eliminating connectors in a variety of product categories and markets.”

NuCurrent has created inductive charging technology based on a proprietary NFC extension. The technology enables up to 3W of power (with plans for 5 watts) received while simultaneously supporting data transfer rates at 108Kb/s and up and enables products such as smart glasses and smart watches to charge wirelessly.  

Technology Trend #5: As adoption of electric vehicles trend upward, EV connectivity solutions are increasing.

As the world shifts towards greener energy, the adoption of wireless charging technologies is set to continue. How energy is captured, stored, consumed, and delivered is of increased importance to consumers. This trend continues to create opportunities for power charging connectors and emerging wireless charging technologies. Wireless charging could disrupt the EV charging connector market, but it’s also likely to drive EV adoption.

WiTricity’s wireless vehicle charging technology (left) uses magnetic resonators and NFC to efficiently transfer power over large distances and is primarily designed for small to mid-size commercial vehicles. PLUGLESS (right) has also developed wireless charging technologies currently compatible with the Tesla Model S, BWM I3, Nissan Leaf, and Gen 1 Chevy Volt. 

While wireless charging technologies may be disruptive to plug-and-play charging stations, they will create other power connector and cable opportunities. In addition, the convenience of wireless charging could likely serve as a catalyst for widespread EV adoption.

Bel Fuse offers Multiple Coil Wireless Charging Coils (WCC) in double and triple winding configurations. The Multiple Coil WCC Series allows power to be transferred wirelessly through inductive coupling and can be used to charge in-vehicle devices like navigation aids, as well as smartphones, gaming devices, wearable medical devices, robotic cleaners, and unmanned aerial vehicles. 

As today’s already-densely connected technologies continue to evolve, creative engineers will continue to develop innovative connectivity products that effectively and reliably overcome new challenges and, in turn, often themselves inspire new design opportunities. We expect the five technology trends addressed here to inspire exciting new products in every market in the coming years.

Contact us to discuss your requirements of 25 Pin Connector. Our experienced sales team can help you identify the options that best suit your needs.