초록 ▼

A technique for self-calibration and phasing of a lens-feed array antenna, while normal operation is stopped, utilizes reflected energy of a continuous and coherent wave broadcast by a transmitter (11) through a central feed (10) while a phase controller (21) advances the phase angles of reciprocal

A technique for self-calibration and phasing of a lens-feed array antenna, while normal operation is stopped, utilizes reflected energy of a continuous and coherent wave broadcast by a transmitter (11) through a central feed (10) while a phase controller (21) advances the phase angles of reciprocal phase shifters (14) in radiation electronics (RE1-REN) of the array elements (1-N) at different rates to provide a distinct frequency modulation of electromagnetic wave energy returned by reflection in one mode (switch 19 closed) and leakage in another mode (switch 19 open) from the radiation electronics of each array element. The composite return signal received by a synchronous receiver (12) goes through a Fourier transform processing system (20) and produces a response function for each antenna element. Compensation of the phase angles for the antenna elements required to conform the antenna response to a precomputed array pattern is derived from the reciprocal square root of the response functions for the antenna elements which, for a rectangular array of N×M elements, is a response function T(n,m). A third mode of calibration uses an external pilot tone from a separate antenna element (44). Respective responses T1(n,m), T2(n,m) and T3(n,m) are thus obtained from the three modes of calibration. From those, the separate responses Tft and Tr of the reciprocal phase shifter, radiation electronics, and synchronous receiver can be obtained by solving the following three simultaneous equations: Tf(n,m)=T1(n,m) Tf(n,m)×Tt(n,m)×Tr(n,m)=T2(n,m) Tf½(n,m)×Tr(n,m)=T3(n,m).

대표청구항 ▼

In a phased array antenna incorporating a separate reciprocal phase shifter in the broadcast path from a central feed to each antenna element, each phase shifter being individually controllable, a method for self-calibration and phasing said array elements to compensate for any deviation from a prec

In a phased array antenna incorporating a separate reciprocal phase shifter in the broadcast path from a central feed to each antenna element, each phase shifter being individually controllable, a method for self-calibration and phasing said array elements to compensate for any deviation from a precomputed pattern from an assumed array structure comprising the steps of broadcasting a continuous coherent reference wave from said feed to said elements, while stopping normal operation and with said phase shifters set to perform a lens operation for said precomputed pattern using said assumed array structure, and receiving at said feed electromagnetic wave energy returned from each phase shifter, advancing the phase angle of said phase shifters at different rates, thereby providing distinct frequency modulation of returned energy from said phase shifters, coherently demodulating the composite of return energy received by said feed, deriving a response function for each antenna element as the Fourier transform of the demodulated return energy, deriving an error signal for each antenna element as the reciprocal of the square root of its response function, and using said error signal for each antenna element for phase compensation of its phase shifter.