Using the planar near field method to measure antenna to get the
antenna performance parameters from the test results; antenna far
field radiation characteristics can be obtained, and diagnosis and
analysis of antennas are made.
Near field measurement (as shown in Fig. 7.1): Using two test ports
of the vector network analyzer as the near field test input and
output ports; under the control of the main control computer, the
output port, under the control of the driving device, through the
test probe on the scanning frame, transmits signals under a certain
scanning mode (single line, bi-directional, stepping); meanwhile,
the other port of the test instrument acquires the test data
through the antenna array, and transmits the data to the main
control computer; the data processing system makes analysis and
diagnosis of the near field characteristics of the antenna array,
and makes the far field parameter calculation.
System composition
a) Scanning frame and probe positioning subsystem
Including the horizontal base (x), vertical tower frame (y), probe
box (z);
b) Antenna mounting frame
Antenna mounting frame is used for installing the 14008 antenna;
the central height coincides with the vertical center of the
scanning frame; which can realize azimuth, pitching, polarization,
forward and backward manual adjustment.
c) Radio frequency subsystem
Including the testing instruments, RF cable, probe, and so on
d) Control computer subsystem
It is the computer hardware used to test the system’s man-machine
interface;
e) Scanning frame and probe positioning control software subsystem
It is a software package to control the scanning frame to move
according to the anticipated way;
f) System main control and test data acquisition software subsystem
It is a software package used to test the system’s man-machine
interface, including various control functions and data acquisition
functions.
g) Test data multifunction processing software subsystem
