Antenna calibration method and apparatus
First Claim
1. For use with a system having an antenna array having a plurality of antennas in a symmetrical arrangement about an axis, a plurality of system ports connected to the plurality of antennas by a corresponding plurality of antenna cables, and a corresponding plurality of transmitters to provide output signals to the plurality of system ports, a method for determining phase offsets necessary to compensate for differences in the antenna cables, the method comprising:
- causing each transmitter of predetermined ones of the plurality of transmitters to drive its corresponding system port with an output signal, the other system ports not being driven;
measuring the phase differences between the output signal at the predetermined, driven system port and return signals at predetermined, non-driven system ports; and
determining differential phase offsets to compensate for the differences in antenna cables based upon the measured phase differences.
3 Assignments
0 Petitions
Accused Products
Abstract
Measurements of frequency and/or phase are taken at the signal ports (S1-S4) of an ISS device (10). These measurements are used to determine phase errors within the ISS device, and phase errors due to the antenna cables (C1-C4). On port, (e.g., S1) is selected as the reference port and then, based on these determined phase errors, offsetting phase errors are determined to correct the phase for the other ports (e.g., S2, S3, S4) with respect to the reference port. The signals at the antenna ports (A1-A4) are then in phase when an omnidirectional antenna pattern is desired from the TCAS antenna array (16). One in embodiment the frequency of the calibration signal is fixed; in another embodiment two different, fixed frequencies are used; and in still another embodiment the frequency is swept to achieve a predetermined measured phase difference.
-
Citations
8 Claims
-
1. For use with a system having an antenna array having a plurality of antennas in a symmetrical arrangement about an axis, a plurality of system ports connected to the plurality of antennas by a corresponding plurality of antenna cables, and a corresponding plurality of transmitters to provide output signals to the plurality of system ports, a method for determining phase offsets necessary to compensate for differences in the antenna cables, the method comprising:
-
causing each transmitter of predetermined ones of the plurality of transmitters to drive its corresponding system port with an output signal, the other system ports not being driven; measuring the phase differences between the output signal at the predetermined, driven system port and return signals at predetermined, non-driven system ports; and determining differential phase offsets to compensate for the differences in antenna cables based upon the measured phase differences. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification