Figure 4
Near-field phase distribution measurement for 4-D antenna array. The transmitting antenna and the receiving antennas can operate at different frequencies. On the transmitting side, 4-D circular antenna array operates at center frequency f 0, connecting with a function signal generator. On the receiving side, both the two receivers operate at the same frequency (harmonic frequency f 0 ± mf p or center frequency f 0). One port of the vector network analyzer connects with a reference antenna to provide reference phase. The other port of the vector network analyzer connects with an open-ended rectangular waveguide that is used as a near-field probe. The measuring plane is 200 mm away from the array plane with a scan range of 500 mm × 500 mm.
