Vehicle telematics incorporating 5G technology! Construct highly reliable vehicle-to-everything with professional ESD solutions

Vehicle telematics is the terminal for the entire vehicleto-everything, providing various information in the vehicle and at the same time serving an external communication channel. In 2020, after 3GPP included 5G NR V2X (5G New-Radio Vehicle–to-everything) into the standard [1], the rate of utilization in the vehicle information and communication systems is increasing year by year. This innovative technology features lower latency and wide coverage, which would dominate the future development of vehicle to everything. The implementation of 5G NR V2X requires more antennas to enable communication for V2X that includes direct communication between vehicles (V2V), connection with infrastructure such as traffic systems and road infrastructure (V2I), and communication with pedestrians (V2P). 5G NR V2X antennas can receive information in real-time, allowing vehicles to respond immediately to the surrounding road conditions. This advantage significantly reduces the occurrence of accidents in autonomous driving scenarios, ultimately achieving a true intelligent transportation system.

ESD events in antennas

However, if 5G NR V2X antennas encounter ESD (Electrostatic Discharge) events, the concept of intelligent transportation might not be so " intelligent " anymore. ESD can potentially disrupt antenna modules, cause signal attenuation, lead to communication interruptions, or reduce data transmission rates. In severe cases, it can even result in complete antenna module failure, thereby affecting the safety and efficiency of V2X. 

Antenna itself is made of metal materials and is less likely to be damaged by ESD. However, when the energy of an ESD event is excessively high, it can impact the "RFIC within the antenna module." Certain RFICs are quite sensitive to ESD, particularly those used in the 5G millimeter-wave frequency range. RFICs in these applications might employ Gallium Arsenide Field-Effect Transistors (GaAs FETs), which have lower ESDimmunity compared to transistors made from silicon [2]. We learn from the above that RF process ICs are relatively more susceptible to ESDcompared to general analog ICs. Among the RFIC components within the antenna, the transceiversare the most critical parts. If they are damaged by ESD, it can result in abnormal circuit functionality and lead to failure of the antenna.

ESD Protection Solutions for Antennas

In order to safeguard components within the antenna module from ESD damage, Amazing Microelectronic Corp. has developed TVS (Transient Voltage Suppressor) solutions specifically designed for 5G antennas, namely AZ9924-01F, AZ9817-01F, AZ9568-01F, and AZ9565-01F. The TVSfor antenna must adhere to specific conditions: (1) Operating voltage: As shown in Figure 1, it's crucial to select a TVS with an appropriate operating voltage during the design phase to ensure that the receiver can receive signals of full power level without the peak voltage being clamped by TVS. Table 1 presents the operating voltages of the TVS as 24 V / 17 V / 8 V / 5 V, allowing for the selection of the operating voltage based on the antenna's transmit power. Additionally, TVS used in antennas should be bidirectional for the same reason mentioned above. (2) Parasitic capacitance: The parasitic capacitance of TVS can lead to losses and variations in the resonant frequency of the antenna [3]. The AZ9568-01F has a low parasitic capacitance of as little as 0.4 pF. This characteristic helps minimize impedance mismatch that could lead to signal distortion. 

The AZ9568-01F has successfully passed AEC-Q101 reliability test, which ensures its safe application in vehicle-mounted environments. Moreover, it has IEC 61000-4-2 ESD immunity of up to 30 kV. With a clamping voltage of 20 V at 8 kV ESD level, it provides optimal protection without compromising the antenna's operation.

Figure 1: I-V Curve of TVS Applied to Antenna

Table 1: List of ESD Protection Device for Antennas

Implementing comprehensive ESD protection measures in V2X is of paramount importance. As a crucial element within the V2X, the vehicle telematics plays a pivotal role in the emerging autonomous driving technology, especially for safety. The antenna module serves as the communication bridge for the vehicle telematics to interact with the external environment. This article documents ESD protection solutions for antenna modules, aiming to offer enhanced protection for the essential components of the vehicle telematics.

[1] 3GPP TS 38.101-1 version 16.5.0 Release 16 (2020) 

[2] J. M. Beall; G. I. Drandova IEEE CSIC-S Dig. 2005, 276-279. 

[3] L. Xu; X. Chen; S. Tan; Z. Hu; B. Ying; T. T. Ye; Y. Li IEEE Sens. J. 2020, 20, 23.