Radiated tests include the antenna and the device as in actual use. Therefore, radiated tests measure the actual RF performance of the device. Tests for measuring antenna performance and parameters are radiated tests but discussed in Antenna tests.
Over-the-Air (OTA) testing is not mandatory in all cases of certification, but usually they are required, for example, by PTCRB and some operators. In spurious emission measurements, the level of interference caused by the device is verified to be under a certain level. The nRF9160 module has been verified to pass these tests in conductive mode, but in radiated mode strong coupling between the antenna and nonlinear components may lead to the creation of TX harmonics that exceed the allowed interference level. Thus, minimizing TX signal coupling from the antenna to other components to avoid failure in spurious emission tests is recommended. Total Isotropic Sensitivity (TIS) and Total Radiated Power (TRP) are active radiated measurements used to test transceivers' performance with the antenna.
In the TIS measurement, receiver sensitivity is measured over a three-dimensional sphere, and the result is averaged. Due to antenna loss, a mismatch loss between the antenna and receiver, as well as noise coupling from the device’s board to the antenna, there is always some gap between TIS and conducted sensitivity.
In the TRP measurement, OTA transmitted power is measured over a three-dimensional sphere and summed to get the total radiated power. Antenna loss and mismatch loss between the antenna and transmitter drop the TRP results compared to conducted TX measurement results.
Active radiated measurements are time consuming. Therefore, antenna performance should be verified by passive antenna measurements before entering active tests.
Radiated functionality tests can be performed in non-signaling mode. This may be useful, for example, in production testing to verify the antenna’s connection to the nRF9160 module as well as its basic functionality.