What is the spherical coverage requirement for 5G FR2 devices and how does it constrain antenna design?

The spherical coverage requirement for 5G FR2 devices specifies that the device must achieve a minimum EIRP (and EIS, Effective Isotropic Sensitivity) over a specified percentage of the directions on the unit sphere surrounding the device. This ensures that the device can communicate with the base station regardless of how the user holds or orients the device. The requirement per 3GPP TS 38.101-2: the UE must meet the EIRP requirement at the 50th percentile CDF (Cumulative Distribution Function) of all measured directions on the sphere. This means: at least 50% of the sphere must have EIRP above the specified minimum. The EIRP at the 50th percentile CDF must be at least: PC3: 11.5 dBm (for n257, n258, n261) and PC4: 22.4 dBm (for n257, n258, n261). Antenna design constraints: cannot rely on a single narrow beam (a single phased array module creates a beam that covers only a small solid angle; the beam can be steered, but: the module has a limited scan range (typically ±60° from broadside); at extreme scan angles: the gain drops significantly (3-6 dB at 60°); the module cannot cover directions behind it (blocked by the phone body). Therefore: multiple modules are needed), module placement (place 2-4 antenna modules at different locations on the phone (top edge, bottom edge, left side, right side) so that their combined coverage approaches the full sphere; even with 4 modules: some blind spots exist (directly behind the phone body, through the battery)), and user hand effects (the user's hand blocks mmWave signals almost completely (20-40 dB attenuation through tissue); the module placement must ensure that at least one module is unobstructed in the most common hand grips).