Issue link: https://resources.mouser.com/i/1484091
16 The Future of Automotive Wi-Fi operates in the 2.4GHz, 5.2GHz and 5.6GHz spectrum, and 2.4GHz Wi-Fi must co-exist with the LTE B40 and B41 frequency bands. 5GHz Wi-Fi enables higher data rates than 2.4GHz because more channels can be bundled together in the 5GHz band thanks to larger bandwidth. This means radio designers must use the correct filter products—those with enough attenuation in adjacent bands to deliver good receiver sensitivity—to get the full benefit of wider bands. Another challenge is 5.6GHz Wi-Fi coexistence with V2X (Figure 2), when a passenger in the autonomous car is using a 5.6GHz hot spot. The only way to have a reliable V2X radio link is to ensure relatively low desense to the receiver. This is only possible with appropriate filter solutions that provide enough out-of-band attenuation to 5.6GHz Wi-Fi (Figures 3 and 4). High-performance Filtering – Why LTCC is Not Enough An ever-increasing array of features is adding to the number of different radios in automobiles, and today there are as many as five radios in a single vehicle (i.e. V2X, 4G/5G, Wi-Fi, Bluetooth, SDARS). This means that multiple radio transceivers are operating in close proximity to each other in different frequency bands. If the transmit power of one RF chain exceeds the power level of the signal reaching a nearby receiver, this can cause receiver sensitivity issues. Coexistence filters help reduce interference issues from these "aggressor signals," which can not only cause receiver sensitivity problems but also result in regulatory non- compliance. However, not all filters that claim coexistence capabilities are suitable for the job. For example, the graphic in Figure 3 compares the performance and system impact of a B47 bulk acoustic wave (BAW) filter with a low temperature co- fired ceramic (LTCC) broadband filter. Figure 2: V2X coexistence with 5GHz Wi-Fi. (Source: Qorvo) Figure 3: Comparison of QPQ2200Q to LTCC: Wideband performance. (Source: Qorvo) ... today there are as many as five radios in a single vehicle...