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4 test methods for 5G base station antenna OTA
Source:Originally | Author:Calio Huang of C&T RF Antennas Inc | Publish time: 2019-05-03 | 861 Views | Share:


Figure1. Far-field test system

(2) Compact field test plan

The compact field test is a far-field test method that uses a mirror or lens to convert a spherical wave from a feed at a focus into a plane wave to achieve far-field testing in a finite physical space. Figure2 shows a parabolic single mirror compact field test system that can test the beamforming pattern of 5G base station antennas and EIRP, EVM, occupied bandwidth, ACLR (Adjacent Channel Leakage Power Ration), Radiofrequency radiation indicators such as EIS and ACS (Adjacent Channel Selectivity).


Figure2. Single mirror compact field test system

(3) Multi-probe spherical near-field test scheme

The near-field test acquires amplitude and phase information in the near-field region of the antenna under test and then converts the acquired data into a far-field pattern by a near-far field conversion algorithm. The multi-probe spherical near-field test system is shown in Figure3. A large number of probes are arranged circumferentially in the near field of the device under test, and the measured object only needs to be rotated by 180° to collect the data of the entire radiation sphere. The system can test the beamforming pattern of a 5G base station antenna in CW (Continuous Wave) mode.


Figure3. Multi-probe spherical near-field test system

(4) Single probe near field test system

The single-probe near-field test is less efficient than the multi-probe spherical near-field test, but its structure is simpler and requires less space. As shown in the small near-field test system shown in Figure 4, the device under test can be rotated in a horizontal plane, the probe can be rotated in a vertical plane, and the system can collect data of a radiation sphere with the cooperation of two rotating shafts. The system can test the beamforming pattern of the 5G base station antenna in CW mode, and can also test the RF radiation index in the service signal mode, but the processing of the test results needs further analysis.