Wireless Connectivity & IoT / V2X

V2X: Technology and Filter Requirements

V2X (Vehicle-to-Everything) is the key technology for connected and autonomous driving, enabling real-time communication between vehicles (V2V), infrastructure (V2I), and pedestrians (V2P). The technology primarily operates in the 5.9 GHz band (5,850 MHz to 5,925 MHz), utilizing either Dedicated Short-Range Communications (DSRC/ITS-G5) or the cellular-based variant C-V2X (PC5 interface). The technical challenge lies in extreme latency sensitivity and the necessity for an absolutely stable connection at high speeds. Since the V2X band immediately borders the high-power Wi-Fi 5 spectrum and future 6 GHz Wi-Fi services, protection against adjacent channel interference is life-critical.

Wainwright Instruments provides specialized high-performance filters for these safety-critical applications, designed to precisely select ITS channels while ensuring extremely steep rejection of neighboring Wi-Fi and cellular signals. To maintain the integrity of time-critical safety messages (CAM/DENM), these filters must exhibit exceptional thermal stability, as they are often installed in the extreme environments of vehicle antennas or Roadside Units (RSUs). Our solutions prevent receiver blocking by strong out-of-band signals and ensure coexistence within complex automotive RF front-end designs.

Typical Deployment Scenarios:

V2X filters from Wainwright are crucial components in systems requiring absolute precision and maximum reliability for the protection of human lives in road traffic.

Vehicle Integrated Communication (OBU): Within On-Board Units, our filters secure V2X communication against on-board high-power transmitters for 5G telematics and in-car Wi-Fi 6E/7.
Intelligent Infrastructure (RSU): In roadside units at intersections or highways, our filter solutions guarantee interference-free detection of vehicle signals, even in environments with high LTE cell density.
Autonomous Driving & Platooning: For the coordinated movement of truck convoys, our filters enable ultra-reliable communication in the 5.9 GHz range to transmit braking and acceleration commands without delay.
Vulnerable Road User (VRU) Protection: In systems for detecting pedestrians and cyclists, our RF solutions secure signal quality to guarantee collision warnings even in RF-burdened urban intersection areas.
Traffic Management & GLOSA: Our components effectively suppress signal interference in the 5.8 GHz range to ensure precise coordination between traffic lights and vehicles for fluid traffic flow.
Electronic Toll Collection: In multi-protocol environments, our filters prevent V2X messages from interfering with DSRC-based tolling transfers or being blocked by them.
Telematics & Fleet Management: For real-time transmission of vehicle diagnostic data, our filters secure necessary bandwidth and signal purity to maintain a stable data connection even under high network load.
Research & Compliance Testing: For validating new V2X components, we supply reference filters with minimal insertion loss to characterize maximum hardware range under real-world conditions and stress tests.

Suitable Filter Categories for Wireless Connectivity & IoT / V2X

High reliability requirements in the automotive sector demand filter solutions that combine extraordinary robustness with extremely steep stopbands.

Band Pass Filters

Our V2X Band Pass filters enable precise selection of ITS channels in the 5.85 GHz to 5.925 GHz range. They are specifically optimized for use in automotive-grade infrastructure systems, combining high selectivity with extremely steep rejection skirts to neighboring Wi-Fi bands. By optimizing phase linearity, we ensure that digital modulation schemes are not distorted, which is the basic requirement for error-free decoding of safety messages. The mechanical precision of our resonators also guarantees minimal insertion loss to conserve the link budget for maximum ranges on highways. Manufacturers of infrastructure components benefit from the high power handling and thermal stability of our filters.

Manually Tunable Band Pass Filters

For the development of V2X antenna systems and validation of protocol stacks in the lab, we offer manually tunable Band Pass filters covering the range from 5.0 GHz to 6.5 GHz. Via high-precision mechanical tuning elements, the passband can be adjusted exactly to specific channels or experimental frequency ranges in different countries (e.g., USA vs. Europe/China). This flexibility allows engineers to investigate the robustness of their systems against targeted broadband interference or neighboring Wi-Fi carriers. The robust construction of our manually tunable filters guarantees permanent reproducibility of measurement results.

Digitally Tunable Band Pass Filters

Electronically controllable filters support modern C-V2X test environments and SDR-based measurement systems that must react agilely to different channels. Via digital interfaces, filter parameters can be adjusted in real-time, which is particularly advantageous for automated test sequences checking channel selectivity. Our digitally tunable filters combine digital control precision with the necessary RF quality and are optimized for use in test environments and development systems. They enable rapid reconfiguration of test scenarios without manual hardware swaps, supporting efficient quality assurance processes in the manufacturing of OBUs and RSUs.

Band Reject Filters / Notch Filters

Our V2X notch filters serve to eliminate specific strong interfering signals located immediately adjacent to the V2X spectrum, such as strong Wi-Fi 5 signals at 5.8 GHz. They feature extremely deep stopband attenuation while the V2X passband remains nearly unaffected. This protection is fundamental to prevent saturation of receivers in RSUs at high-traffic sites with many mobile hotspots. By using our notch filters, the robustness of the infrastructure against narrowband interferers is massively increased, significantly increasing the reliability of safety communication in urban metropolitan areas.

Manually Tunable Band Reject Filters / Notch Filters

Frequency-tunable notch filters provide a flexible solution for interference suppression directly in the field during the commissioning of roadside units. By manually adjusting the stopband frequency, interfering signals caused, for example, by other industrial radio systems or poorly performing Wi-Fi installations can be masked immediately. This ensures the availability of V2X services without waiting for new filter hardware. The mechanical precision of our filters guarantees that once a stopband frequency is found, it remains stable even under strong vibrations and temperature fluctuations on bridges or masts.

Digitally Tunable Band Reject Filters / Notch Filters

In intelligent traffic infrastructures, digitally tunable notch filters enable an automated response to dynamic interference scenarios. Controlled by monitoring algorithms, these filters can dynamically mask interfering signals in real-time to maintain Quality of Service for critical applications such as hazard warnings. Their integration into automation concepts for radio optimization allows for autonomous radio optimization of entire highway sections. Thanks to remote controllability, operators can adjust filter characteristics centrally, reducing operating costs and massively increasing the resilience of V2X infrastructure against new interference sources at shared mounting locations.

Monoplexer / Diplexer / Duplexer / Triplexer

Combining V2X with other radio standards like 5G telematics or Wi-Fi 6E on a shared vehicle antenna requires high-performance multiplexers with extremely high isolation. Our diplexers for 5.9 GHz separation enable simultaneous use of infotainment services and safety communication with minimal mutual interference. Wainwright Instruments manufactures these components with a focus on minimal insertion loss and maximum robustness against thermal cycles in the vehicle. Precise tuning prevents signal crosstalk and protects sensitive V2X receiver paths from overloading by their own high-power transmitters. Our multiplexers are optimized for use in professional traffic infrastructure applications and industrial RSUs.

Absorptive Filters

Absorptive filters play a crucial role in the transmission infrastructure of V2X test systems and high-power RSUs to preserve signal purity. Rather than conducting unwanted harmonics or reflections back to the transmitter, these filters safely convert them into heat, preventing signal distortion. This is particularly important for complying with strict regulatory masks for spectral power density in the ITS band. Our absorptive filters are designed for continuous operation and increase communication precision by consistently minimizing thermal stress and signal reflections.