Omnetics Spring 2019 Newsletter
In this Issue:
- Nano Connectors for Unmanned Applications
- Nano 360® Circular Connectors for High Reliability
- From the Engineer's Desk: Coax Impedance
- Did you know?
- On the Road With Omnetics
Nano Connectors for Unmanned Applications
As technology continues to evolve, Unmanned Aerial Vehicles (UAVs) are being utilized and expanding in a variety of industries. You can find them spraying pesticides over crops or using imaging technology to monitor crop growth and health. They are used by public safety and first responders to aid with search and rescue missions and wildfire monitoring. UAVs are established in the oil and gas industry to inspect and monitor equipment and pipelines. Survey engineering has utilized UAV technology to monitor structural health and conduct geological surveys and site inspections. Most of these applications require high precision data acquisition systems along with complex flight control systems and stable communication with ground systems to run smoothly.
Managing size and weight are the main challenges associated with evolving UAV technology. As the need for more instrumentation and electronics on board UAVs grows, designers and engineers are continuously challenged to fit everything on board the aircraft. Designers are always looking for ways to pack in technology without sacrificing performance.
For example, on a typical quadcopter, there will be a flight controller that has multiple circuit boards containing gyros, accelerometers, along with processors and memory required to run the flight software. There’s also GPS, video transmitters, power distribution boards, and black-box data logging. Fitting all of these systems in a package that can maneuver properly for all types of flight missions can prove to be difficult for designers and engineers.
As many UAV’s trend towards miniaturization, connector size and weight becomes a factor in the design. Connectors are needed for routing signals from instruments and flight controllers to control surfaces, motors, and sensors. There are also typically connectors on the circuit boards, and as the boards get smaller in size or higher in density, connectors associated with them must shrink. They are continuously being pushed to their limits. Omnetics’ high density Nano-D connectors, at .025” spacing between contacts, are a great, high-reliability solution for slimming down connectors while keeping all the signals desired on the board.
Miniaturization is not the only technology trend in the UAV industry. High-speed data transfer is becoming a standard requirement in many UAV sub-systems. Next-generation sensors and instruments on board collect data at increasing rates, and data link sub-systems must be able to support these higher speeds and high data rates. Connectors that can support higher speeds are necessary as well. Omnetics’ Nano Coax is one solution that shrinks down a standard 50 ohm coax solution to ¼ the size of a standard SMA.
The Nano Coax is available as a cable to cable, a vertical board mount, and a horizontal board edge mount as a solution for all types of size restrictions and was designed to minimize losses and maintain impedance through the connector. It is also available as a hybrid solution in the Micro-D package or in a circular package (no current board option). These options allow the designer to incorporate multiple coax and signal contacts within one set of connectors, gaining the space and weight needed within the UAV environment.
As on-board flight instruments become more advanced and flight systems evolve, the need for miniaturization of connectors and data link systems is more present than ever. UAV designers choose Omnetics’ connectors for their on board flight hardware because they offer high density, unmatched reliability, and high speed data transfer in a variety of packages.
Nano 360® Circular Connectors for High Reliability
Instrument mobility, portable medical equipment, miniature surveillance systems, and many other applications require quick and easy cable connections. These connections must be very highly reliable to meet the shock, vibration, and temperature demands placed on these systems. As electronic instruments, cameras, and sensors continue to get smaller, the need for easy plug-and-go functions evolves. Connector systems and the instruments in which they are used may need to be replaced on the field, requiring small size, light weight, and thousands of mates and de-mates of the connector. Previous standards for connector-to-cable systems, such as MIL-DTL-38999 and D-subminiature connectors, are quite often too large, too heavy and are prone to failure in this new electronics environment. The miniaturization of circuits and other instruments demands miniaturized connector and cabling systems.
Nano 360® Circular connectors from Omnetics are designed to significantly reduce size and weight while maintaining high reliability. They use the same key elements of Nano-D connectors that have passed military specifications for shock, vibration, durability, temperature, and mating/de-mating force and passed specifications for MIL-DTL-32139. Nano 360® Circular connector contacts are spaced at a pitch of 0.025 inches (0.64 mm), and are available with standard contact counts of 6, 11, 16, 28, and 39 positions. They are extremely lightweight at 0.6 – 2.3 grams, including wire. Omnetics has reduced the overall size and weight by as much as 3x compared to standard .050” spaced circular connectors. The gold plated pin and sockets have higher insertion and withdrawal forces that further help ensure connector retention in rugged environmental applications.
Pins and sockets inside the Omnetics’ Nano 360® Circular connectors are gold plated Beryllium Copper. Combined with Liquid Crystal Polymer or Polyphenylene Sulfide insulators, these connectors are capable of over 2,000 mates and de-mates. Standard products come pre-wired with 18” of 32 AWG Teflon insulated copper wire that handles 1 AMP of current per contact. Nano 360® Circular connectors are capable of withstanding temperatures from -55°C to 125°C (200°C with HTE). Overmolds are also available, which bond the cable and connector to provide a pre-wired connector to cable design.
Nano 360® Circular connectors are available in four distinct shell types:
- Plastic—provides the lightest weight while remaining extremely durable. Low-profile clips and locks are available for added security.
- Threaded—offering a positive lock and environmental seal. Waterproof up to IP68 and available in panel mount configurations.
- Breakaway—designed to release or “break away” at a predetermined force of roughly 4 lbs. Waterproof up to IP 68 and available in panel mount configurations.
- Twist-Lock—mates and de-mates with a simple quarter turn of the socket-side coupling nut. Waterproof up to IP68 and available in panel mount configurations.
Nano 360® Circular connectors have found success in a variety of different markets. Current applications include helmet electronics, surveillance equipment, miniature robotic systems, surgical tools, and soldier-worn portable communications systems. More information on Circular connectors from Omnetics is available.
From the Engineer's Desk: High Speed Connector Design
by Ryan Satrom, Signal Integrity Engineer
Impedance is a critical parameter for coax cables and connectors. Since impedance is not relevant for most low-frequency applications, many designers may not be familiar with impedance and its importance. In the second installment in our series on coax cables and connectors, we will look deeper into impedance.
What is Impedance?
In its most basic definition, impedance is the ratio of the voltage to the current of a signal path. However, though technically accurate, this definition may not help us understand its application to cables and connectors.
To better understand this, consider water flow through a simple pipe where ideal flow is achieved with optimal pipe diameter. If the diameter of the pipe changes, the water flow will be impacted. Similarly, if impedance changes—either increases or decreases—from the specified value (typically 50Ω or 75Ω), the signal will be degraded, causing issues in the system.
The target impedance of any path is defined by the circuitry that transmits and receives the signals. This impedance must be matched for all components in the path. Accordingly, cable and connector manufacturers do not define the impedance for a given application. Instead, they design their products to fit the impedance that the application specifies.
Whenever the impedance through a path deviates from the specified application impedance, a mismatch occurs and some of the signal, designed to transmit through the path, will reflect back to the source causing signal degradation.
How is Impedance Calculated?
Coax impedance is determined by the ratio of insulator diameter to signal diameter. In order to increase the impedance, either the insulator diameter must be increased or the signal diameter must be decreased. Actual impedance values are determined through simple coax equations or a variety of electromagnetic solvers.
Why 50 Ohms?
Theories abound as to why 50Ω became the standard, but the most popular explanation says that it was determined as a compromise between best power transfer (30Ω) and lowest signal loss (77Ω). This allows the 50Ω standard to be used for both power and signaling applications. Since the most important aspect of a good design is to make sure all impedances are matched, the actual value becomes an important yet secondary value.
Why 75 Ohms?
75Ω coax is typically used for transmitting video and other data signals. Since power is rarely transferred over these cables, 75Ω is used because it provides very low signal loss through the path.
Strengths & Weaknesses
There are many applications where coax is used. The next installment will look into the strengths and weaknesses of coax, helping engineers determine where best to implement this technology.
Did you know?
Goldman Sachs estimates that the drone market will grow to $100 billion by 2020. The largest market for drones is the military, but commercial and consumer markets make up a percentage of the market. Construction and agriculture are the largest commercial users of drones.
Omnetics connectors are popular in drones and UAVs for their small size, light weight, and extreme durability. Check out our products page to find the connector for your needs.
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