Temperature and frequency compensated array beam steering unit

Claim 3

The method as defined by claim 1 and additionally including the step of multiplying the phase gradient signal by a number corresponding to element position on the array and generating thereby a fine phase signal and thereafter utilizing said fine phase signal as said phase shifter drive signal.

Claim 4

The method as defined by claim 2 wherein said memory comprises a digital memory, wherein said step of converting said sensed temperature to an electrical signal comprises converting the temperature signal to a digital temperature signal, wherein said step of generating an electrical signal indicative of the operating frequency comprises the step of generating a digital frequency signal, and wherein said step of combining both electrical signals comprises summing the digital temperature and frequency signals and generating thereby a digital memory address signal or pointer for said digital memory.

Claim 5

The method as defined by claim 3 wherein said digital memory includes a set of stored values of the term 2πd/λ, where d is the separation between the radiating elements and λ is inversely proportional to frequency, and wherein said function of the beam steering angle comprises the function sin θ, where θ is the beam steering angle.

Claim 6

The method as defined by claim 1 wherein said phase shifters and said radiating elements receive RF energy of a selected operating frequency by way of a power divider and additionally including the further steps of: sensing the temperature of the power divider; converting the sensed temperature of the power divider to an electrical signal; combining the power divider temperature signal with the operating frequency signal and generating therefrom another memory address signal; addressing another memory, said another memory having a set of stored values of feed phase corrections compensated for both temperature and operating frequency; reading out a predetermined feed phase correction value from said another memory in accordance with said another memory address signal; combining said predetermined phase gradient value and said predetermined feed phase correction value into a composite signal; and utilizing said composite signal as said phase shifter drive signal.

Claim 7

The method as defined by claim 5 and additionally including the step of multiplying said composite signal by a number corresponding to a radiating element position and generating thereby a fine phase signal; utilizing said fine phase signal as said phase shifter drive signal; and wherein said step of coupling said drive signal to said set of phase shifters comprises coupling said fine phase signal to said set of phase shifters in a predetermined sequence.

Claim 8

The method as defined by claim 6 wherein said converting steps comprise converting the respective electrical signals to digital signals, said memories comprise digital memories respectively storing digital values of phase gradients and feed phase corrections, and wherein said combining steps include generating respective digital memory address signals for addressing said digital memories.

Claim 9

The method as defined by claim 7 wherein said set of stored values of beam steering phase gradients comprises a set of digital values of the term 2πd/λ where d is the spacing between said radiating elements, and λ is proportional to frequency, and wherein said set of stored values of feed phase corrections comprises a set of digital values of the term 2πd/λ g where d also comprises the spacing between said radiating elements and λ g is the wavelength of energy propagating in said power divider, and said function of the beam steering angle comprises the function sin θ where θ is the beam steering angle.

Claim 10

The method as defined by claim 7 wherein said combining steps comprise the steps of summing the digital signals indicative of aperture temperature and operating frequency to generate a first digital memory address signal and summing the digital signal indicative of power divider temperature and operating frequency to generate a second digital memory address signal.

Claim 11

Apparatus for electronically compensating for beam pointing errors and sidelobes resulting from temperature and frequency changes on a phased array antenna comprising: a linear array of a plurality of equally spaced radiating elements including a mechanical aperture; a set of phase shifters coupled to said radiating elements for controlling the phase of RF energy radiated from respective elements and generating a composite radiated beam having a phased radiant thereacross; a power divider for coupling RF energy of a predetermined operational frequency to said phase shifters from a common source; means for sensing the temperature at least of said antenna aperture; means for converting the sensed antenna aperture temperature to an electrical temperature signal; means for selecting one of a plurality of operating channel frequencies of RF energy radiated from the radiating elements; means for generating an electrical frequency signal of the selected channel frequency; means for combining both electrical temperature signal and the electrical frequency signals and generating therefrom a memory address signal; a memory including a set of stored values of beam steering phase gradients compensated for both aperture temperature and operating frequency, said memory address signal reading out a predetermined value of phase gradient from said digital memory; means for generating a beam steering angle command signal; means for multiplying the predetermined value of the beam steering phase gradient read out from said memory by the sine function of the beam steering angle to generate a coarse phase gradient signal; means for multiplying the coarse phase gradient signal by a number corresponding to element position and generating thereby a fine phase signal; and means for coupling said fine phase signal to said set of phase shifters in a predetermined sequence for radiating a compensated beam from said array at said beam steering angle.

Claim 12

Apparatus for electronically compensating for beam pointing errors and sidelobes resulting from temperature and frequency changes on a phased array antenna comprising: a linear array of a plurality of equally spaced radiating elements including a mechanical aperture; a set of phase shifters coupled to said radiating elements for controlling the phase of RF energy radiated from respective elements and generating a composite radiated beam having a phased radiant thereacross; a power divider for coupling RF energy of a predetermined operational frequency to said phase shifters from a common source; means for sensing the temperature at least of said antenna aperture; means for converting the sensed antenna aperture temperature to an electrical temperature signal; means for selecting one of a plurality of operating channel frequencies of RF energy radiated from the radiating elements; means for generating an electrical frequency signal of the selected channel frequency; means for combining both electrical temperature signal and the electrical frequency signals and generating therefrom a memory address signal; a memory including a set of stored values of beam steering phase gradients compensated for both aperture temperature and operating frequency, said memory address signal reading out a predetermined value of phase gradient from said digital memory; means for generating a beam steering angle command signal; means for multiplying the predetermined value of the beam steering phase gradient read out from said memory by the sine function of the beam steering angle to generate a coarse phase gradient signal; means for multiplying the coarse phase gradient signal by a number corresponding to element position and generating thereby a fine phase signal; and means for coupling said fine phase signal to said set of phase shifters in a predetermined sequence for radiating a compensated beam from said array at said beam steering angle.

Claim 13

The apparatus as defined by claim 10 wherein said memory comprises a digital memory including a set of addressably stored digital values of phase gradients.

Claim 14

The apparatus as defined by claim 11 wherein said electrical temperature and frequency signals comprise digital signals and wherein said means for combining both said signals for generating a memory address signal comprises an address computational logic circuit which is operable to add said digital signals.

Claim 15

The apparatus as defined by claim 12 wherein said digital memory includes a set of stored values of the term 2πd/λ, where d is the spacing between radiating elements, and λ is a function of the frequency of the RF signal radiated from said elements.

Claim 16

Apparatus for electronically compensating for beam pointing errors and sidelobes resulting from temperature and frequency changes on a phased array antenna fed RF energy of a predetermined operating frequency selected from a plurality of operating channel frequencies comprising: a plurality of equally spaced radiating elements arranged in a linear array and driven by a plurality of phase shifters, one for each element; a power divider coupling a common source of RF energy of said predetermined operating frequency to each phase shifter; means for sensing the temperature of said antenna; first converting means for converting the sensed temperature to a first electrical temperature signal; means for sensing the temperature of said power divider; second converting means for converting the sensed temperature of said power divider to a second electrical temperature signal; means for generating an electrical signal indicative of said operating frequency; first signal combining means for combining said first electrical temperature signal and said electrical signal indicative of the operating frequency and generating a first memory address signal; second signal combining means for combining said second electrical temperature signal and said electrical signal indicative of the operating frequency and generating second memory address signals; a first memory responsive to said first memory address signal and having a set of retrievably stored values of beam steering phase gradients compensated for both temperature and operating frequency and providing a predetermined phase gradient value output signal in response to a particular first memory address signal; a second memory responsive to said second memory address signal and having a set of retrievably stored values of feed phase corrections compensated for both temperature and operating frequency and providing a predetermined feed phase correction value output signal in response to a particular second memory address signal; means for generating a beam steering angle command signal; means for operating on the predetermined phase gradient value from said first memory by a function of the beam steering angle to generate a coarse phase gradient signal; means for combining the coarse phase gradient signal and the predetermined phase correction signal provided by said second memory to provide a composite drive signal; said composite signal being utilized to drive said phase shifters for radiating a compensated beam from said array at said beam steering angle.

Claim 17

Apparatus for electronically compensating for beam pointing errors and sidelobes resulting from temperature and frequency changes on a phased array antenna fed RF energy of a predetermined operating frequency selected from a plurality of operating channel frequencies comprising: a plurality of equally spaced radiating elements arranged in a linear array and driven by a plurality of phase shifters, one for each element; a power divider coupling a common source of RF energy of said predetermined operating frequency to each phase shifter; means for sensing the temperature of said antenna; first converting means for converting the sensed temperature to a first electrical temperature signal; means for sensing the temperature of said power divider; second converting means for converting the sensed temperature of said power divider to a second electrical temperature signal; means for generating an electrical signal indicative of said operating frequency; first signal combining means for combining said first electrical temperature signal and said electrical signal indicative of the operating frequency and generating a first memory address signal; second signal combining means for combining said second electrical temperature signal and said electrical signal indicative of the operating frequency and generating second memory address signals; a first memory responsive to said first memory address signal and having a set of retrievably stored values of beam steering phase gradients compensated for both temperature and operating frequency and providing a predetermined phase gradient value output signal in response to a particular first memory address signal; a second memory responsive to said second memory address signal and having a set of retrievably stored values of feed phase corrections compensated for both temperature and operating frequency and providing a predetermined feed phase correction value output signal in response to a particular second memory address signal; means for generating a beam steering angle command signal; means for operating on the predetermined phase gradient value from said first memory by a function of the beam steering angle to generate a coarse phase gradient signal; means for combining the coarse phase gradient signal and the predetermined phase correction signal provided by said second memory to provide a composite drive signal; said composite signal being utilized to drive said phase shifters for radiating a compensated beam from said array at said beam steering angle.

Claim 18

The apparatus as defined by claim 14 and additionally including means for multiplying said composite signal by a number corresponding to each element position of said array and generating thereby a fine phase signal, said fine phase signal being coupled to each phase shifter in a predetermined sequence according to element position.

Claim 19

The apparatus as defined by claim 15 wherein said array comprises a series-fed array and wherein said phase shifters comprise a first set of phase shifters for one half of said radiating elements and a second set of phase shifters for the other half of the radiating elements and wherein said fine phase signal is applied to the respective phase shifter of said first and second sets of phase shifters in the same sequence.

Claim 20

The apparatus as defined by claim 15 wherein said first and second memory address signals comprise digital address signal pointers, said first and second memories being comprised of digital memories and being responsive to said digital address signal pointers to provide digital output signals of said phase gradients and feed phase corrections.

Claim 21

The apparatus as defined by claim 17 wherein said function of the beam steering angle comprises the sine function.

Claim 22

The apparatus as defined by claim 18 wherein said first digital memory includes a set of stored values of the term 2πd/λ, where d is a measure of the physical separation between radiating elements, and λ is inversely proportional to frequency, and wherein said second digital memory includes a set of stored values of the term 2πd/λ g where d is also said separation between radiating elements and λ g is inversely proportional to the frequency of RF energy propagating in said power divider.

Claim 23

The apparatus as defined by claim 17 and additionally including a first temporary memory coupled from said first converting means to said first combining means for temporarily storing said first electrical temperature signal, a second temporary memory coupled from said means generating said operating frequency signal to said first and second combining means for temporarily storing said operating frequency signal, and a third temporary memory coupled from said second converting means to said second combining means for temporarily storing said second electrical temperature signal, said temporary memories being operable to periodically couple the respectively stored electrical signals of temperature and operating frequency to said first and second combining means.

Claim 24

The apparatus as defined by claim 20 wherein said first and second combining means are comprised of digital address computational logic means.