By Nick Murata, Product Marketing, and Jack Ozeki, Field Application Engineer, I-PEX Connectors
Features and Applications of Micro-Coaxial Cable
As high-speed Internet improves and the usage of large-capacity memory devices increases, high-quality images and videos can be enjoyed more easily on consumer products such as PCs, tablets and smartphones. The amount of information that needs to be processed on the device has dramatically increased and the signal speed (transmission standard) in the device has been getting faster and faster.
Cables and FPC/FFC are mainly used for jumper connections when transferring signals and power between module boards in devices. To some extent, the types of cables and FPC/FFC that can support are determined by the signal speed (signal transmission standard) and transmission distance. In general, coaxial cables* are considered suitable for high-speed or long-distance signal transmission. (*Coaxial cable referenced above includes micro-coaxial cable and twinax cable.)
With the recent increase in signal transmission speed, the usage of micro-coaxial cables for jumper connections in devices is expanding.
Signal Transmission Advantages of Micro-Coaxial Cable
Signal transmission characteristics are affected by a variety of parameters such as characteristic impedance, insertion loss, return loss and crosstalk. Below are some of the main reasons why micro-coaxial cables are generally considered to have signal transmission advantages when a high-speed signal is transmitted.
- Return Loss Reduction: The center conductor, dielectric and outer conductor in micro-coaxial cables are suitable for matching and are stabilized at specific impedance. Matched and stabilized impedance creates a low return loss.
- Insertion Loss Reduction: A micro-coaxial cable can secure a larger cross-sectional area of the center conductor compared to FPC/FFC when matching to specific impedance, which minimizes the reduction of insertion loss.
- High Shielding Performance: The outer conductor works as an electromagnetic shield, so the electrical signal transmitted on the center conductor is less susceptible to electromagnetic waves (electromagnetic noise) from the outside. In addition, the shielding effect of the outer conductor also helps to reduce crosstalk between signal lines.
Flexibility of Micro-Coaxial Cable
Oftentimes micro-coaxial cable is used because it has a higher degree of flexibility compared to shielded FPC / FFC and it can stabilize the electrical characteristics even if it is bent. Flexible micro-coaxial cables are suitable for devices with hinges that require the cables to be moved and routed within the device, such as hinge on notebook PCs and rotating cameras on drones. With the number of applications that include high resolution cameras and panels on the rise, along with higher signal transfer speeds, micro-coaxial cables that combine high-speed signal characteristics and mechanical advantages are a preferred solution.
Connectors for Micro-Coaxial Cable (Micro-Coaxial Connectors)
Connectors for micro-coaxial cable, also known as micro-coaxial connectors, are used to connect signals between module boards using micro-coaxial cables. To perform appropriate signal transmission, the center conductor which transmits the signal, needs to be connected to the signal circuit on the board via the contacts of the connector. The outer conductor of the cable needs to be electrically connected on the board via metal parts of the connector referred to as the shell. The electrical connection of the outer conductor to board through the connector shell is called “grounding.”
EMI Shielded Connectors
As electronic devices are evolving to be more high-performance, power-saving, and compact, the high-speed signal requirement in these devices increases, the number of electronic components operating at low voltage increases and the density of mounted electronic components increases. If electromagnetic noise is added from the outside, unnecessary current may be induced to the circuits in the devices causing a malfunction or damage to high-performance electronic components which may also lead to electronic device breakage. In addition, in electronic devices with wireless communication functions (for example, notebook PCs, tablets and mobile phones) electromagnetic waves generated within the devices can add to the wireless communication circuit noise which could reduce antenna reception performance. EMI shielded connectors solve electromagnetic noise from the connector with appropriate grounding structure and cover which includes the mounting position of the signal contact tails with metal shields. This solution is widely adopted by many customers to prevent electromagnetic interference, especially in high-performance devices equipped with wireless communication functions such as Wi-Fi®, GPS, and LTE.
For more information about micro-coaxial solutions from I-PEX Connectors, click here: https://bit.ly/32q3TUZ.
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