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34 Next-Gen Connectivity for Smart Living Low-low aggregations create some of the most difficult antenna design problems. Mobile phones typically support low-band frequencies using two primary antennas located at the top and bottom of the phone. These antenna locations minimize the likelihood that user interactions with the phone will impair performance because consumers generally position their hands at the sides of phones, not at the top and bottom. A critical problem is that low-low aggregations may need a third antenna capable of low-band transmissions. That means manufacturers need to find yet more space for this antenna within the handset and ensure that the chosen antenna location provides adequate performance under all use conditions. Higher Transmit Power The higher power output defined in the PC 2 and PC 1.5 specifications impacts smartphone battery life. It also means that all post-PA components within the RFFE, including antenna tuners, must handle more power. This generally means that components will need to be larger, which is problematic given the significant space constraints. The increased output power also means RFFE components will generate higher levels of spurious signals, requiring additional attention to mitigating desense and RSE issues. New Designs Reduce Space for Antennas New handset designs with foldable and rollable screens create a whole array of antenna challenges. The phone must be able to operate in different physical states—rolled or unrolled, folded, or open—which severely limits the potential locations for antennas, and may also require the use of different antenna materials. Adding to the challenge, the constraints imposed by the design may mean that antennas must be placed in suboptimal locations that make their performance more susceptible to human interaction. Antenna grounding may be affected, impacting radiation efficiency. Careful antenna design and positioning will be needed to ensure efficient operation in all use conditions. The replacement of mechanical buttons with software- defined virtual buttons creates additional antenna challenges. Locating these buttons along the bottom of the phone maximizes convenience and the screen space available to users. However, this also means that they may interfere with the primary antenna traditionally placed in this location. QPA9442 High Linearity Driver Amplifiers LEARN MORE > QPQ3509 RF Filters LEARN MORE >