(i9) United States
(12) Patent Application Publication oo) Pub. No.: US 2007/0069945 Al
Weese (43) Pub. Date: Mar. 29,2007
(54) CALIBRATION METHOD FOR SMART ANTENNA ARRAYS
(75) Inventor: Kurt Weese, Ditzingen (DE)
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON, DC 20037 (US) (73) Assignee: ALCATEL
(21) Appl. No.: 11/517,308
(22) Filed: Sep. 8, 2006
(30) Foreign Application Priority Data
Sep. 28, 2005 (EP) 05 292 023.8
(51) Int. CI.
G01S 7/40 (2006.01)
(52) U.S. CI 342/174
The invention relates to a method of calibrating the reception path and the transmit path of an antenna array which comprises at least three antennas and which is connected to a digital signal processor. For calibrating the reception path a signal of known amplitude and known phase is transmitted by a single antenna, whereby this signal is received by the other n-1 antennas, whereby a phase difference and an amplitude difference between each of the n-1 transmitted signals is evaluated. The last two steps are repeated with a new transmit antenna until every antenna has been used as a transmit antenna. In the last step the phase differences and their associated amplitude differences are set to the factorysaid values. For calibrating the transmits path of an antenna array 1 comprising at least three antennas and being connected to a digital signal processor, a method comprises the step transmitting a signal of a known amplitude and known phase by n-1 antennas and receiving these signal by the n antenna, evaluating a phase difference and an amplitude difference between each of the n-1 transmitted signals, repeating the last two steps with a new receiving antenna until every antenna has been used as a receiving antenna, compensating the phase differences and their associated amplitude differences to the factory-set values.