The introduction of fifth-generation wireless technology, popularly called 5G, has disrupted the automotive industry. 5G automotive, with its breakneck speeds, improved connectivity, and reduced latency, will transform how cars work.

The adoption of 5G will make vehicles much safer and more efficient. The "future of 5G in connected cars" involves a strategic integration of internal and external antennas facilitating high-speed, low-latency, and reliable communication between the car and the 5G network. Such 5G communication will enable various applications like advanced driver-assistance systems (ADAS), real-time traffic updates, remote diagnostics, and seamless entertainment experiences. As the 5G infrastructure continues to evolve, connected cars will become increasingly sophisticated and capable of harnessing the full potential of this transformative technology.

The drive for 5G

Cars running on future 5G networks will need enhanced mobile broadband, massive machine-type communications (mMTC), and ultra-reliable and low-latency communications. Consumers demand enhanced mobile broadband, where gigabytes of data can be transferred in milliseconds. mMTC authorises intermittent data transmission, allowing the emergence of smart cities with 5G-connected lampposts, stop lights, and buildings controlling traffic flow. Connected agricultural systems in rural areas improve crop yields and lower food costs. Ultra-reliable and low-latency communications are crucial for high-stake infrastructures such as self-driving cars, remote patient monitoring, and industrial automation. These approaches drive the demand for greater connectivity in the near future.

The future of 5G in the connected car

5G offers new commercial opportunities for the automotive industry and improves road safety. Road operators can use the data harvested from connected vehicles to ensure safe traffic flows and avoid accidents. Critical alerts, such as left-turn assistance, will support drivers in challenging situations. The 5G-based infrastructure allows relaxed driving experiences, with traffic-light-optimised speed-advisory systems and self-driving vehicles using privileged lanes for convenient driving and mobility. The vision of zero-accident cars is possible with 5G.

The connected vehicle as part of the IoT environment
Figure 1: The connected vehicle as part of the IoT environment

Car manufacturers favour in-car safety and security sensors to ensure the safety of the driver. Car sensors enable autonomous driving and detect traffic congestion and alternative route selection without a network. The new 5G-based infrastructure will create a less stressful driving experience, with traffic-light-optimised speed-advisory systems regulating traffic from intersection to intersection and self-driving vehicles using privileged lanes for convenient driving and mobility. With 5G, the ambitious vision of zero-accident vehicles is within reach.

Signal integrity management

The industry uses Non-Standalone (NSA) New Radio (NR) for 3G and 4G at sub-6GHz frequencies. However, for 5G communications, the long-term goal is to combine sub-6GHz and frequency spectra between 24GHz and 100GHz. The 5G frequency allocation is divided into two bands, FR1 and FR2. The current New Radio (NR) standard supports frequencies ranging from 600 MHz to over 50 GHz with different signal characteristics between the lower and upper limits of the 5G frequency range.

The FR1 band is divided into a low band (600 to 700 MHz) and a midband (2.5 to 3.7 GHz). These frequencies accommodate WiFi, GPS, Bluetooth, Zigbee communication signals, and other non-communication devices. The second band, FR2, contains millimeter wavelength (mmWave) frequencies ranging from 24 to 39 GHz. The higher the frequency, the faster the data rates. Low-band frequencies offer 4G-like 25 to 200 Mbps downloads, whilst the FR2 band allows a 20 Gbps downlink. Millimeter waves have wavelengths around 1cm to 1mm, relating to a frequency range of approximately 30 GHz to 300 GHz.

Managing signal integrity (SI) becomes increasingly difficult with rising frequency. The increased speeds come with a tradeoff: propagation is constrained to line-of-sight (LOS), faster attenuation over distance, and more difficulty penetrating buildings and dense vegetation. These losses can be compensated by deploying more cells, especially in urban environments. Various cell configurations are available to deal with the realities of millimeter-wave frequencies.

Challenges relating to omni-directional antennas and signal strength

The automotive industry is optimistic about the future of 5G, but challenges remain when integrating mobile communications with antenna technology. Currently, signals are transmitted via cable connections from an antenna on a vehicle's roof to the onboard electronics. With the need for more bandwidth, 5G will explore a wider operating frequency range from 6 to 100 GHz, requiring electronics to be positioned close to the antenna. However, fluctuating weather conditions and high temperatures can negatively impact the performance and operating lifecycle of the electronics. The expansion of the frequency range increases radio field attenuation, causing signals to be received only from a shorter distance. This results in problems with omnidirectional antennas, which cannot receive signals or only do so to a limited extent. Roadside units must also be equipped with directional antennas to transmit the signal to devices in passing cars. Some antenna manufacturers are working together to solve this problem. 5G will use FR2, the extended mmWaves frequency band, ten times broader than the LTE band.

Antenna solutions

Antennas are crucial in wireless high-speed communications, enabling information sharing, seamless in-car entertainment, and IoT expansion. 5G devices need re-designed and highly optimised antennas to support new frequencies and transmission methods. The 5G Massive MIMO network is more interference-resistant and uses beamforming to maximise signal transmissions.

Antennas are common in modern automotive design, with up to two dozen fitted to every vehicle. Molex provides custom antenna solutions for any connectivity requirement. These are designed and tested to meet the exact specifications of automotive and commercial vehicle OEMs. Their engineers employ industry-leading RF expertise to develop best-in-class antennas that ensure superior connectivity.

Antennas need to be installed at strategic positions inside and outside the safe environment of the cabin, linking to the body control module (BCM) system. Designers need access to internal and external antenna solutions to enable keyless functionality in modern vehicles. They will need a PCB-mounted antenna with a small footprint and a sealed external one for non-cabin installation.

Each vehicle sends massive amounts of data. The system employs multiple-input multiple-output (MIMO) transmitters and receivers to transfer large quantities of data simultaneously. The latest solution for this demanding requirement is the integrated, multi-in-one antenna that supports a range of MIMO technologies, including 5G NR 4x4/LTE MIMO and WiFi MIMO—incorporating multiple WIFI 5G antennas as GNSS solutions for navigation. These multi-antenna solutions will provide the bandwidth needed for the high volumes of data necessary for autonomous vehicles.

External antennas

Molex offers Cabled External Antennas, which provide superior RF performance in ruggedised thermoplastic enclosures. These antennas can perform in various environments, including high moisture, corrosive chemicals, extreme temperatures, shock and vibration. Molex's expertise in ruggedised connection systems and enclosures has been applied to external antennas, offering standard adhesive, magnetic, and bolt-down options. Both antennas and cables are available in standard configurations and can be customised. Molex's expanding line of innovative antenna products includes off-the-shelf LTE/5G antennas for 2G/3G/4G/5G modules and devices. These antennas offer superior coverage, reliability, high efficiency, and peak gain, making them ideal for different wireless and networking applications. The multi-protocol solution supports GSM, CDMA, UMTS, LTE, 5G NR, and other cellular bands, making them suitable for diverse applications.

LTE/5G cellular external antennas
Figure 2: LTE/5G cellular external antennas

Internal antennas

Internal antennas such as the windshield or roof are integrated within a vehicle's structure, providing aesthetically pleasing protection. However, metal bodies can cause interference and may impact performance. External antennas outside the vehicle offer better signal reception and are used for applications such as autonomous driving and real-time communication. However, they can be visually unappealing and susceptible to damage. Molex leverages its industry-leading expertise and capabilities to design and manufacture custom antenna solutions for wireless and mobile applications, concentrating on small multiband and complementary antennas by employing MID/LDS, flex, stamped, and ceramic technologies.

MID/LDS technology offers flexibility and 3-dimensional design freedom for molded interconnect devices. It provides engineering services and manufacturing processes from one vendor, ensuring quality, consistency, and economic efficiencies. LDS technology supports multi-antenna integration into one device.

Combo antennas

Molex combo antennas provide expanded frequency ranges for multiple wireless communication protocols, long-range connectivity, high-power efficiency, and easy integration. As WiFi/GPS applications become smaller, they demand smaller but higher-performance antennas covering the full GNSS band. Molex's compact 2.4/5 GHz Combo GPS/WiFi Ceramic Antenna is a cost-competitive solution.

Advanced WiFi applications require robust antennas for high barrier penetration and reliable connectivity. Molex's Triple-Band Ceramic Antennas with WiFi HaLow compatibility are interference-resistant, support larger but lower frequency ranges than 2.4/5 GHz connections, operate with lower power over longer ranges, and enable multiple device support. Wireless communication developers prefer antennas that can be integrated immediately, and Molex GPS/WiFi Combo Balanced PCB and Flexible Antennas are dipole-style with a balanced-transmission design.

5G connectors

Connectors in mmWave-based systems face geometry, size, and material selection challenges while matching the transmission line's characteristic impedance. Impedance matching is essential for reducing signal reflection and maximising power transfer. 5G connectors must handle higher power than previous generations, with a potential 15A+ instantaneous current draw. Design considerations include short RF terminals, increased shielding, and unique shielding placement. Advanced 5G applications require PCB space savings, a price-to-performance ratio, and various design features to suit customer applications. The 5G15 connector offers maximum PCB space savings, supports frequencies up to 15 GHz, and features EMI shielding, robust mating, and pin assignment for power and high-speed signal options. Its over-mold design prevents pin pullout, whilst strong and large power and ground nails prevent damage to interconnects during mating.

The 5G15 Series connector is highly versatile, replacing multiple coaxial cables over an FPC cable, supporting 5G mmWave, Sub 6 GHz, and 4G/LTE applications, and combining RF or non-RF connections in a single connector. Pin assignment for power and high-speed signals can be flexible in antenna modules with 2 RF + 1.0A power or 4 RF without power configurations.

The 5G25 series connector offers industry-leading SI performance for high-frequency (25 GHz) needs, thanks to Molex's proprietary contact shielding and isolation of RF terminals. The connectors' delicate nature places the responsibility of high electrical reliability on their makers, as they must be robust to withstand rough handling or rigorous operating conditions. Design flexibility is critical for these connectors to suit a broad spectrum of industry applications. The unique plug and receptacle design of the 5G25 series addresses the mobile, wearables, and 5G industry's requirements for easy-to-deploy RF connectors that are easily and readily deployable in assembly processes requiring mating tolerance allowance whilst maintaining electrical contact reliability.


Molex, a connectivity solutions provider, can impact the future of 5G in connected cars by offering advanced antennas, antenna integration, signal enhancement, IoT connectivity, and innovation. By designing and manufacturing high-performance internal and external antennas, Molex can cater to specific vehicle needs, ensuring optimal signal reception while maintaining aesthetics. Additionally, Molex can develop technologies to counteract signal interference caused by vehicle metal structures, improve internal antenna performance, and contribute to efficient data exchange between vehicles and the IoT ecosystem.


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