The current mainstream WLAN tests now support three types of MIMO tests. The three types of MIMO are: True MIMO, Composite MIMO, and Switched MIMO.

Three MIMO tests are introduced:

1. True MIMO: Each antenna of the DUT needs to be tested with an instrument respectively, which can support various TX and RX test items of the DUT.

2. Composite MIMO: The multiple antennas of the DUT are combined through the power splitter to complete the test in unison with one RF port of the instrument. Only the TX test of the DUT is supported, and the reference files of each TX signal need to be generated in advance.

Figure 2: Composite MIMO wiring method

3. Switched MIMO: The multiple antennas of the DUT are connected to different RF ports of the same instrument to complete the test. Only the TX test of the DUT is supported, and the DUT must continuously transmit the same signal during the test; the number of antennas that can be tested is limited The number of RF ports of the instrument;

Figure 3: Switched MIMO wiring

The wiring methods of the three test schemes are different, and the tester needs to choose the corresponding wiring method according to the actual situation.

The advantages and disadvantages of the three MIMO methods: