Method and system for testing antenna array using middle field antenna pattern

A method for testing an antenna array of a device under test (DUT) using a probe antenna for receiving a radio frequency (RF) signal beam from the antenna array, the antenna array comprising a plurality of antenna elements, the method comprising:

• measuring actual radiated power of an antenna pattern for a main lobe of the signal beam of the antenna array using the probe antenna located at an actual distance and direction from the antenna array, the actual distance being in a middle field of the antenna array, wherein the middle field satisfies near field criteria for the antenna array, and also satisfies far field criteria for each antenna element of the plurality of antenna elements in the antenna array;
• selecting a correction number from a previously populated correction table using the actual distance and direction from the antenna array, and an actual size of the antenna array, including a number of antenna elements comprising the antenna array;
• and
• determining a far field antenna pattern for the main lobe of the signal beam of the antenna array at a position in a far field of the antenna array by adding the selected correction number to the measured actual radiated power of the antenna pattern.

A test system for determining an antenna pattern of an antenna array of a device under test (DUT), the antenna array comprising a plurality of antenna elements, the test system comprising:

• an antenna probe positioned in a middle field of the antenna array, wherein the middle field includes a distance between the antenna probe and the antenna array that satisfies near field criteria for the antenna array, as a whole, and separately satisfies far field criteria for each antenna element of the plurality of antenna elements in the antenna array;
• at least one receiver configured to receive radio frequency (RF) signal beams transmitted from the DUT via the antenna array;
• a memory that stores a correction table populated with predetermined correction data comprising differences between far field antenna patterns from different positions in a far field of the antenna array and a middle field antenna pattern from a position in the middle field of the antenna array;
• and
• a processor programmed to:
• measure radiated power of an antenna pattern for a main lobe of an RF signal beam of the antenna array at a first position relative to the antenna array using the probe antenna, the first position being located in the middle field of the antenna array;
• retrieve predetermined correction data from the correction table corresponding to a second position relative to the antenna array located in the far field of the antenna array, the second position corresponding to one of the different positions in the far field of the antenna array included in the correction table;
• and
• determine the antenna pattern of the antenna array in the far field of the antenna array by translating the measured radiated power of the antenna pattern for the main lobe of the RF signal beam of the antenna array from the first position in the middle field to the second position in the far field of the antenna array by adding the retrieved predetermined correction data to the measured radiated power.