Local compensation of failed elements of an active antenna array

Claim 3

The method of claim 1 wherein the step of adjusting the phase and voltage includes the steps of dividing the magnitude of the voltage signal which would have been radiated by the failed element if it were working properly by the number of said local compensators to determine a voltage factor by which to increment the voltage of the signal radiated by each local compensator.

Claim 4

The method of claim 1 wherein the step of adjusting the phase and voltage further includes the step of determining a selected phase to be assigned to each local compensator.

Claim 5

The method of claim 2 wherein the step of adjusting the phase and voltage further includes the step of determining a selected phase increment assigned to each said voltage factor.

Claim 6

The method of claim 3 wherein said selected phase is determined so as to scan the voltage increment at a selected depression angle.

Claim 7

The method of claim 3 wherein said step of determining a selected phase further includes the step of determining a first phase increment by adding the phase of the original failed element to a phase increment Δφ and determining a second phase increment by subtracting Δφ from the phase of the original failed element.

Claim 8

The method of claim 6 wherein said phase increment Δφ is determined according to the equation: ##EQU13## where s is the vertical spacing of the compensating elements above and below the failure; λ is the wavelength of the emitted signal; and θ is a desired depression angle.

Claim 9

The method of claim 7 wherein the desired depression angle θ is 30 degrees.

Claim 10

The method of claim 4 wherein the selected voltage at the selected phase for each respective local compensator are added to the original complex voltage assigned to the respective local compensator to form an adjusted compensator voltage.

Claim 11

The method of claim 7 wherein the selected voltage at the selected phase for each respective local compensator are added to the original complex voltage assigned to the respective local compensator to form an adjusted compensator voltage.

Claim 12

The method of claim 9 wherein, if the magnitude of the adjusted compensator voltage exceeds the saturation amplitude of the local compensator element, the magnitude of the adjusted compensator voltage is set to said saturation value.

Claim 13

The method of claim 10 wherein, if the magnitude of the adjusted compensator voltage exceeds the saturation amplitude of the local compensator element, the magnitude of the adjusted compensator voltage is set to said saturation value.

Claim 14

The method of claim 1 wherein said failed element and the plurality of adjacent elements is a diamond lattice with said failed element lying at the intersection of first and second diagonal line segments, said local compensators comprising first, second, third, and fourth said elements, one disposed at each end of said first and second line segments.

Claim 15

The method of claim 11 wherein said failed element and the plurality of adjacent elements is a diamond lattice with said failed element lying at the intersection of first and second diagonal line segments, said local compensators comprising first, second, third, and fourth said elements, one disposed at each end of said first and second line segments.

Claim 16

The method of claim 1 wherein said failed element and the plurality of adjacent elements is a rectangular lattice comprising a matrix of rows and columns of elements and wherein a single element immediately above said failed element and a single element immediately below said failed element are selected as local compensators.

Claim 17

The method of claim 11 wherein said failed element and the plurality of adjacent elements is a rectangular lattice comprising a matrix of rows and columns of elements and wherein a single element immediately above said failed element and a single element immediately below said failed element are selected as local compensators.

Claim 18

The method of claim 1 wherein said step of locating includes the steps of: evaluating the performance of a plurality of modules of said array, wherein said step of evaluating comprises the steps of: determining an FFT power spectrum related to the operation of said module, said spectrum including a power component related to the module under test and a plurality of additional power components; and comparing selected said components to evaluate the performance of said module.

Claim 19

The method of claim 1 wherein each element of said array includes a transmit phase shifter and a receive phase shifter, and said step of locating includes the step of testing each element of the array to detect a failed element, each element being tested by: turning off all elements of the array but one, said one element comprising an element under test; cycling said element under test through alternating receive and transmit states; shifting the phase of the element under test after each successive pair of receive and transmit states; sampling first and second signals, the first signal being representative of the transmit phase shifter output, the second signal being representative of the receive phase shifter output, said first signal being sampled during each transmit state, said second signal being sampled during each receive state; collecting the output samples taken in the receive state into a first set and those taken in the transmit state into a second set; determining the average power in a succession of Fourier transform filters taken over the samples of said first set; determining the average power in a succession of Fourier transform filters taken over the samples of said second set; and comparing the power in selected said filters and rejoicing the element under test as failed based upon said comparison.

Claim 20

The method of claim 18 wherein said samples comprise the output of a receiver supplied with in-phase and quadrature phase signals and wherein one output sample is collected for each phase state through which the element under test is shifted for both the transmit and receive states.