Communications: directive radio wave systems and devices (e.g. – Directive – Including a steerable array
Reexamination Certificate
2000-08-09
2001-09-25
Phan, Dao (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a steerable array
C342S174000
Reexamination Certificate
active
06295027
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of calibrating the transmitting and receiving branches of a group antenna.
2. Prior Art
Group antennas are described in International Application WO 95/31403. In these known group antennas a predetermined transmission signal is fed to the individual antenna elements in each transmitting branch for calibration of the transmitting branches and the superimposed signal on it is decoupled at the end of each transmitting branch. The signal decoupled at the end of each signal branch is compared with the predetermined transmission signal fed into it. A deviation found from the comparison of the signals is compensated by an amplitude and phase adjustment in the appropriate transmission branch.
A calibration of the receiving branch occurs by feeding a predetermined reception signal into the individual receiving branches and again decoupling the superimposed signal on it at the end of receiving branches. An adjustment of the amplitude and phase in the concerned receiving branch is performed depending on the shift between the signal that is fed in and decoupled signal in each receiving branch. This prior art calibration method does not balance or compensate for errors caused by the antenna elements, since the transmission behavior of the antenna elements are not considered in this method.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a calibration method of a group antenna of the above-described kind, with which the transmitting and receiving branches of the group antenna can be calibrated including the antenna elements belonging to them in as simple a manner as possible.
According to the invention the method comprises the steps of:
a) sending a respective calibrating signal over a plurality of corresponding transmitting branches one after the other;
b) detecting superimposed signal components coupled into respective individual antenna elements of the group antenna for each calibrating signal sent over the corresponding transmitting branches in the receiving branches belonging to the respective individual antenna elements;
c) deriving amplitude and phase variations of a transmission function of each of the transmitting branches or receiving branches relative to a transmission function of a reference transmitting or receiving branch from received signals including the superimposed signal components detected in the corresponding receiving branches for all calibrating signals; and
d) adjusting amplitude adjusting elements and phase adjusting elements in the respective individual transmitting branches or in the receiving branches so that the amplitude and phase variations derived in step c) are minimized.
Electronic controllable duplex group antennas are used in radar and communication systems, when the antenna propagation diagram required in transmission and reception applications must have a flexible shape with a high spatial selectivity. In practice an exact form for the antenna propagation diagram is only possible with group antennas, when the variations of the transmission properties of the individual receiving and transmitting branches necessarily present are exactly known and compensated. A calibration of the group antenna in which the transmission properties of the receiving and transmitting branches are adjusted in regard to amplitude and phase is thus required from time to time. With the method according to the invention the calibration may be performed with comparatively little effort considering the transmission properties of the individual antenna elements.
Advantageous further embodiments of the invention are claimed and described in the dependent claims appended hereinbelow.
A quotient is formed from the transmission function determined for the other transmitting or receiving branches and the transmission function of the reference transmitting or receiving branch. This quotient is used as an adjustment parameter for the adjusting of the amplitude and phase elements in the transmitting and receiving branches.
Advantageously a transmitting or receiving branch is selected as the reference transmitting or receiving branch whose transmission function is approximately one.
In order to compensate for measurement errors it is advantageous to derive an average adjustment parameter for each transmitting or receiving branch by forming the respective transmission function quotients with respect to several reference transmitting or receiving branches and to find the average quotient.
In a group antenna whose antenna elements are arranged linearly with equal spacing, the transmitting or receiving branches preferably are adjusted to equal amplitude and phase values, beginning in the center of the linear group antenna and continuing toward the antenna elements on the outside.
Errors in adjusting the amplitude and phase elements can be corrected by performing several redundant measurements of the transmission functions for determination of the adjusting parameters and performing an averaging of the measurements.
REFERENCES:
patent: 5086302 (1992-02-01), Miller
patent: 5940032 (1999-08-01), Passmann et al.
patent: 6157343 (2000-12-01), Anderson et al.
patent: 2 346 013 (2000-07-01), None
patent: 95/34103 (1995-12-01), None
Wiegmann Mark
Wixforth Thomas
Phan Dao
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Method of calibrating a group antenna does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of calibrating a group antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of calibrating a group antenna will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2449796