Intermodulation grating lobe suppression method
First Claim
1. A method of suppressing intermodulation grating lobe beams in an antenna pattern in a field of view of a phase array antenna system of a plurality of antenna elements, the method comprising the steps of,regularly spacing the plurality of antenna elements into subarrays, each of the subarrays comprising a plurality of regularly spaced antenna elements of the plurality of antenna elements, regularly spacing the subarrays for generating a null in the antenna pattern in the field of view of the phased array antenna system, generating two modulated carrier signals respectively at a first carrier frequency and a second carrier frequency, phase shifting the two modulated carrier signals into respective first and second sets of phase shifted modulated carrier signals, summing the first and second sets of phase shifted modulated carrier signals into a plurality of summed modulated carrier signals, amplifying the plurality of summed modulated carrier signals into amplified modulated carrier signals, the amplifying of the plurality of the summed modulated carrier signals creating intermodulation products in the intermodulation grating lobe beams within the field of view, and transmitting through the plurality of antenna elements the two amplified modulated carrier signals, the regular spacing of the subarrays and the regular spacing of the antenna elements in each of the subarrays tending to cancel the intermodulation products for decreasing the intermodulation grating lobe beams by effectively positioning the null upon intermodulation grating lobe beams.
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Accused Products
Abstract
A grating lobe suppression method is applied to a phased array antenna system having antenna array elements that are grouped in regularly spaced subarrays each having a plurality of regularly spaced antenna elements within the subarrays for suppressing intermodulation grating lobes generated within a field of view of the antenna system when amplifying two modulated carrier communication signals at respective two different frequencies.
60 Citations
9 Claims
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1. A method of suppressing intermodulation grating lobe beams in an antenna pattern in a field of view of a phase array antenna system of a plurality of antenna elements, the method comprising the steps of,
regularly spacing the plurality of antenna elements into subarrays, each of the subarrays comprising a plurality of regularly spaced antenna elements of the plurality of antenna elements, regularly spacing the subarrays for generating a null in the antenna pattern in the field of view of the phased array antenna system, generating two modulated carrier signals respectively at a first carrier frequency and a second carrier frequency, phase shifting the two modulated carrier signals into respective first and second sets of phase shifted modulated carrier signals, summing the first and second sets of phase shifted modulated carrier signals into a plurality of summed modulated carrier signals, amplifying the plurality of summed modulated carrier signals into amplified modulated carrier signals, the amplifying of the plurality of the summed modulated carrier signals creating intermodulation products in the intermodulation grating lobe beams within the field of view, and transmitting through the plurality of antenna elements the two amplified modulated carrier signals, the regular spacing of the subarrays and the regular spacing of the antenna elements in each of the subarrays tending to cancel the intermodulation products for decreasing the intermodulation grating lobe beams by effectively positioning the null upon intermodulation grating lobe beams.
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8. A method of suppressing intermodulation grating lobe beams in an antenna pattern in a field of view of a phased array antenna system of a plurality of antenna elements, the method comprising the steps of,
regularly spacing the plurality of antenna elements into subarrays, each of the subarrays comprising a plurality of regularly spaced antenna elements of the plurality of antenna elements, regularly spacing the subarrays for generating a null in the antenna pattern in the field of view of the phased array antenna system, generating two modulated carrier signals respectively at a first carrier frequency and a second carrier frequency, the first and second carrier modulated signals producing first and second primary main beams transmitted by the plurality of antenna elements, the first and second primary main beams appearing in the field of view, phase shifting the two modulated carrier signals into respective first and second sets of phase shifted modulated carrier signals, the phase shifting serving to space the primary main beams within the field of view, the phase shifting also serving to dispose secondary intermodulation main beams outside the field of view and serving to dispose the intermodulation grating lobe beams within the field of view, summing the first and second sets of phase shifted modulated carrier signals into a plurality of summed modulated carrier signals, amplifying the plurality of summed modulated carrier signals into amplified modulated carrier signals, the amplifying of the plurality of the summed modulated carrier signals creating intermodulation products of the intermodulation grating lobe beams within the field of view, and transmitting through the plurality of antenna elements the two amplified modulated carrier signals, the regular spacing of the subarrays and the regular spacing of the antenna elements in each of the subarrays tending to cancel the intermodulation products for decreasing the intermodulation grating lobe beams by effectively positioning the null upon intermodulation grating lobe beams within the field of view.
Specification