Beamforming utilizing a surface acoustic wave device

Claim 2

A beamforming apparatus for processing the outputs of a linear array of spaced apart receiving elements comprising: a surface acoustic wave (SAW) device having a pair of transducers mounted on a substrate in a spaced apart relationship, each transducer being capable of receiving and converting an electrical chirp signal into an acoustic signal for propagation across the surface of the SAW device; the substrate of the SAW device having a zinc oxide layer on a silicon/silicon oxide base; a plurality of taps, wherein each tap is adapted to receive a bias voltage, mounted on the substrate in a spaced apart relationship between said pair of transducers for operating in cooperation with the substrate to receive, square and convert the acoustic signals back into electrical signals; the spacing between the taps being proportionally matched to the spacing between the receiving elements; means for mixing the signal from each tap with a signal from a respective receiving element so as to produce a plurality of mixed output signals; and means for summing the mixed output signals so as to provide a summed output signal.

Claim 3

A beamforming apparatus as claimed in claim 1 including: a video device; and an upper sideband device for processing the summed output signal and for feeding the upper sideband thereof to said video device.

Claim 4

A beamforming apparatus as claimed in claim 1 including: means for applying a bias voltage to each tap.

Claim 5

A beamforming apparatus as claimed in claim 1 including: means for generating the chirp signals; and the chirp signals being linear FM chirp signals with the same starting frequency, but of opposite slope.

Claim 6

A beamforming apparatus for processing the signal outputs ω m of a linear array of m equi-spaced apart receiving elements comprising: means for generating a pair of chirp signals g 1 (t) and g 2 (t) wherein the signals are linear FM chirps with the same starting frequency, but of opposite slope; a surface acoustic wave (SAW) device having a pair of transducers with the same center frequency ω o mounted on a substrate in a spaced apart relationship, each transducer being capable of receiving and converting a respective chirp signal into an acoustic signal so that the acoustic signals from both transducers are propagated toward one another across the surface of the SAW device; the substrate of the SAW device having a zinc oxide layer on a silicon/silicon oxide base; n taps mounted on the substrate between said pair of transducers in an equi-spaced apart relationship for operating in cooperation with the substrate to receive, square, and convert the acoustic signals back into electrical signals; means for generating a plurality of bias voltages V n , each tap being connected to the bias voltage generating means for receiving a respective bias voltage; the resulting potential Φ n2 (t) on the n th tap being ##EQU6## where: B=a proportionality constant based on the tap bias voltage, D=the distance between the center of the device between said transducers and the middle of the first tap, δ=the tap spacing, Δx=the tap width, t=time in reference to the center of the device between the transducers, x=the distance from the center of the device between the transducers, and V=velocity of the acoustic waves across the device; means for mixing the signal Φ n2 (t) from each tap with a respective signal ω m from a corresponding receiving element so as to produce a plurality of mixed outputs S 1 (t) where ##EQU7## where ##EQU8## d=the array element spacing; and means for summing the mixed output signals so as to provide a summed output signal S o (t) where ##EQU9##

Claim 7

A beamforming apparatus for processing the signal outputs ω m of a linear array of m equi-spaced apart receiving elements comprising: means for generating a pair of chirp signals g 1 (t) and g 2 (t) wherein the signals are linear FM chirps with the same starting frequency, but of opposite slope; a surface acoustic wave (SAW) device having a pair of transducers with the same center frequency ω o mounted on a substrate in a spaced apart relationship, each transducer being capable of receiving and converting a respective chirp signal into an acoustic signal so that the acoustic signals from both transducers are propagated toward one another across the surface of the SAW device; the substrate of the SAW device having a zinc oxide layer on a silicon/silicon oxide base; n taps mounted on the substrate between said pair of transducers in an equi-spaced apart relationship for operating in cooperation with the substrate to receive, square, and convert the acoustic signals back into electrical signals; means for generating a plurality of bias voltages V n , each tap being connected to the bias voltage generating means for receiving a respective bias voltage; the resulting potential Φ n2 (t) on the n th tap being ##EQU6## where: B=a proportionality constant based on the tap bias voltage, D=the distance between the center of the device between said transducers and the middle of the first tap, δ=the tap spacing, Δx=the tap width, t=time in reference to the center of the device between the transducers, x=the distance from the center of the device between the transducers, and V=velocity of the acoustic waves across the device; means for mixing the signal Φ n2 (t) from each tap with a respective signal ω m from a corresponding receiving element so as to produce a plurality of mixed outputs S 1 (t) where ##EQU7## where ##EQU8## d=the array element spacing; and means for summing the mixed output signals so as to provide a summed output signal S o (t) where ##EQU9##

Claim 8

A beamforming apparatus as claimed in claim 5 including: a video device; and an upper sideband device for processing the summed output signal and for feeding the upper sideband thereof said said video device.

Claim 11

A method as claimed in claim 7 including: extracting the upper sideband of the summed output signal and feeding the extracted signal to a video device.