Contactless connectivity is an emerging technology. A few initial applications for contactless connectors include USB SuperSpeed, Gigabit Ethernet, DisplayPort, PROFINET, EtherCAT, and single-pair Ethernet (SPE). Contactless connectors are specialized mmWave transceivers that replace traditional wired connectors and provide cable-free, high-speed connections between devices that are closely spaced, usually up to a few centimeters apart (Figure 1).
Figure 1. Wireless connectors can transmit data at high speeds across spaces up to several centimeters (Image: Rosenberger).
This FAQ begins with a review of the modes of contactless connectivity, looks at some of the anticipated benefits of using contactless connectivity, then takes a deeper dive into anticipated applications for the technology, and closes by looking at some performance capabilities of a typical design.
Contactless connectivity has three modes of operation:
- Simplex connectivity transmits data in one direction without any ability to send data in the reverse direction. It’s useful for signaling applications that don’t require any response.
- Half-duplex connectivity supports data transmission in both directions but not simultaneously. Application examples include connecting individual monitors on a video wall and wireless docks for laptop computers.
- Full-duplex connectivity supports simultaneous data transmission between two devices. This mode reduces latency compared to half-duplex and is sometimes implemented using two half-duplex devices working together. For example, one full-duplex contactor solution can deliver data rates of 5 Gigabits per second (Gbps) when implemented with two pairs of devices and 10 Gbps when implemented with four pairs. Application areas are expected to include docking stations, ruggedized laptops, augmented reality and virtual reality devices, and factory automation systems.
What are the benefits?
Contactless connectivity minimizes the need for cables, wiring, and physical connectors on printed circuit boards. That can result in sleeker, more compact, and lighter-weight designs. In addition, this technology can eliminate the need for diagnostic ports, further streamlining device designs.
Contactless connectors are sealed, making them suitable for applications in harsh environments where dust, dirt, and moisture can be of concern. They are also rated for broad temperature ranges like 0° to +70° C for commercial devices and extended ranges like -30° to +85° C. The lack of cables and mechanical connectors reduces the effects of vibration and other mechanical stresses.
Manufacturability, speed of production, configurability, and testability can all be improved since there is no need to attach physical connectors.
Contactless connectors are not powerless
Mechanical connectors don’t need power. That’s not the case for contactless connectors. They typically operate with low voltages like 1.2 or 1.8 Vdc. Exemplary current draws are 77mW for transmitting and 100mW when receiving at a data rate of 1 Gbps. The current draw usually varies with the data rate; not all contactless connector solutions are the same. The need to balance current draw and transmission speed is a new factor that designers need to consider that does not exist with mechanical connectors.
More application possibilities:
- Tiling individual displays into a video wall is simplified since no physical connections are needed. The lack of physical connectors improved reliability in outdoor environments.
- Increasing the Ingress Protection (IP) rating of ruggedized networking equipment, including waterproof designs.
- Eliminating repetitive cable bending in industrial robots improves reliability.
- Smartwatches, smartphones, and VR/AR gear can benefit from the small size of contactless connectors (a typical device is 3.00 x 3.00 x 0.90 mm), resulting in lighter and more compact designs.
- Medical devices involved in sterilization can have reduced risks of exposing electronics to harsh environments, heat, and vibration.
- Self-driving vehicles like autonomous mobile robots can have simplified wiring harnesses, reducing weight and improving reliability.
What does that look like?
Contactless connectors are designed to easily integrate with existing communication protocols and systems like Gigabit Ethernet (GigE) (Figure 2). They include an integrated timer to optimize signal integrity at higher data rates.
Commonly available data rates include 1, 3, and up to 5.4 Gbps. An integrated antenna further simplifies system design. They’re based on 60 GHz wireless technology and are unaffected by Bluetooth, Wi-Fi, or wireless charger interference. These devices use amplitude-shift keying (ASK) modulation and have an output power of -0.8 dBm, a typical receiver sensitivity at 5.4 GPBs of -21.3 dBm, and an antenna gain of 6.5 dBi.
Figure 2. Contactless connectivity can be integrated directly with existing GigE and other communications protocols (Image: Molex).
Summary
Contactless connectors are an emerging technology that promises to benefit many applications, including consumer, industrial, automotive, and medical devices. They can operate at high data rates and support many common communications protocols.
References
- Contactless connectivity to connect the future, Radiall
- High-Speed and Power-Efficient Contactless Transmission, Rosenberger
- MX60 Gigabit Ethernet Contactless Connectivity Solutions, Molex
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