Null steering antenna
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsGene R. Marner, Nathan Marchand
Life of this patent
Estimating the term…
Abstract
Where there is a difference in the angle of arrival between desired incom signals and interfering signals, the reception of the desired signals is maximized by the creation of nulls in the direction of the interfering signals. A high quality receiving (or transmitting) beam is formed by a one-time calculation of the proper phase or amplitude adjustment required to create a null in the direction of each interfering signal. The antennae are then appropriately adjusted to establish the nulls.
Claims20
In an antenna system of n antenna wherein a desired signal arrives in the general direction of main receiving beam and an undesired signal arrives in a direction at least slightly different from the direction of said desired signal;
- said main receiving beam having a main lobe in the direction of said desired signal and a minor lobe in the direction of said undesired signal, a method for generating a high quality beam in the direction of said desired signal and a null in the direction of said undesired signal comprising the steps of:
- calculating the progressive phase shift (.phi.) necessary to create a maximum in said main lobe;
- calculating the progressive phase shift (.alpha.) required to create a maximum in said minor lobe;
- determining the phase of said minor lobe relative to the voltage of said main beam;
- determining the amplitude of said minor lobe;
- calculating the ratio (k) of the amplitude of said minor lobe relative to the peak amplitude of said main beam;
- calculating the phase relationship (.gamma.) between said minor lobe and said main beam at peak amplitude;
- calculating the value of 2 k sin [.gamma.-n(.phi.-.alpha.)] for each of said n antennae;
- computing the arc tangent of each said value thereby determining the required phase shift for each antenna;
- and
- adding each said required phase shift to the corresponding antenna thereby establishing said null and said high quality beam.
In an antenna system of n antennae wherein a desired signal arrives in the general direction of a main receiving beam and an undesired signal arrives in a direction at least slightly different from the direction of said desired signal;
- said main receiving beam having a main lobe in the direction of said desired signal and a minor lobe in the direction of said undesired signal, a method for generating a high quality beam in the direction of said desired signal and a null in the direction of said undesired signal, comprising the steps of:
- calculating the progressive phase shift (.phi.) necessary to create a maximum in said main lobe;
- calculating the progressive phase shift (.alpha.) required to create a maximum in said minor lobe;
- determining the phase of said minor lobe, relative to the voltage of said main beam;
- determining the amplitude of said minor lobe;
- calculating the ratio (k) of the amplitude of said minor lobe relative to the peak amplitude of said main beam;
- calculating the phase relationship (.gamma.) between said minor lobe and said main beam at peak amplitude;
- calculating the value of 2 k cos [.gamma.-n(.phi.-.alpha.)] for each of n antennae thereby determining its required amplitude variation;
- and
- adding each said required amplitude variation to the corresponding antenna thereby establishing said null and said high quality beam.
In an antenna system of n antenna wherein a desired signal arrives in the general direction of a main beam and undesired signals arrive in a direction at least slightly different from the direction of said desired signal;
- said main beam having a main lobe in the direction of said desired signal and a minor lobe in the direction of each said undesired signal, a method for generating a high quality beam in the direction of said desired signal and a null in the direction of each undesired signal comprising the steps of:
- calculating the progressive phase shift (.phi.) necessary to create a maximum in said main lobe;
- calculating all progressive phase shifts (.alpha.) required to create a maximum in each minor lobe;
- determining the phase of each minor lobe relative to the voltage of said main beam;
- determining the amplitude of each minor lobe;
- calculating all ratios (k) of the amplitude of each minor lobe relative to the peak amplitude of said main beam;
- calculating all phase relationships (.gamma.) between each minor lobe and said main beam at peak amplitude;
- for each null, repeatively follow the steps of calculating the value of 2 k sin [.gamma.-n(.phi.-.alpha.)] for each of said antenna and with each calculation of said value taking into account the adjustments made in establishing any previous nulls;
- computing the arc tangent of each said value thereby determining the required phase shift for each antenna;
- and adding each required phase shift to the corresponding antenna thereby establishing a null in the direction of one of said undesired signals.
In an antenna system of n antennae wherein a desired signal arrives in the general direction of a main beam and an undesired signal arrives in a direction at least slightly different from the direction of said desired signal;
- said main beam having a main lobe in the direction of said desired signal and a minor lobe in the direction of each said undesired signal, a method for generating a high quality beam in the direction of said desired signal and a null in the direction of each undesired signal comprising the steps of:
- calculating the progressive phase shift (.phi.) necessary to create a maximum in said main lobe;
- calculating all progressive phase shifts (.alpha.) required to create a maximum in each minor lobe;
- determining the phase of each minor lobe relative to the voltage of said main beam;
- determining the amplitude of each minor lobe;
- calculating all ratios (k) of the amplitude of each minor lobe relative to the peak amplitude of said main beam;
- calculating all phase relationships (.gamma.) between each minor lobe and said main beam at peak amplitude;
- for each null, repetively follow the steps of calculating the value of 2 k cos [.gamma.-n(.phi.-.alpha.)] for each of n antennae, with each value calculation taking into account the adjustments made in establishing any previous nulls;
- adding each said value calculated to the corresponding antenna thereby establishing a null in the direction of one of said undesired signals.
A null steering antenna for creating a main receiving beam in the direction of a desired signal and a null in the direction of each undesired signal comprising:
- (a) an array of antennae positioned in the signal field;
- (b) null determining means for computing the phase shift value of the arc tangent of 2 k sin [.gamma.-n(.phi.-.alpha.)] which is required to create each null;
- (c) adjustment means responsive to said null determining means for adjusting the phase of each antenna;
- (d) summing means to add the adjusted signals from said antennae;
- and
- (e) receiver means connected to the output of said summing means which thereby experiences a highly directional reception pattern that is receptive to signals arriving from the direction of said desired signal and virtually nonreceptive to signals arriving in the direction of said nulls.
A null steering antenna for creating a main receiving beam in the direction of a desired signal and a null in the direction of each undesired signal comprising
- (a) an array of antennae positioned in the signal field;
- (b) null determining means for computing the amplitude variation value of 2 k cos [.gamma.-n(.phi.-.alpha.)] which is required to create each null;
- (c) adjustment means responsive to said null determining means for adjusting the amplitude of each antenna;
- (d) summing means to add the adjusted signals from said antennae;
- and
- (e) receiver means connected to the output of said summing means which thereby experiences a highly directional reception pattern that is receptive to signals arriving from the direction of said desired signal and virtually non-receptive to signals arriving in the direction of said nulls.
Dependencies are inferred from the claim text.