摘要 |
A phased-array antenna (18) for use with a frequency-hopping transmitter (16) includes a plurality of elemental antennas (210), each associated with a phase-shifter (212) which is controlled (20) to form a beam (216) in the desired direction at a base frequency. The antenna elements (210, 212) are formed into subarrays (408t, 408b) each of which is fed from a common port (310). A further phase-shifter (312) is associated with each subarray, for imposing a phase shift on a group of elements of the overall array. The further phase-shifters are controlled when the frequency of the transmitter is away from the base frequency, to cause a stepwise-continuous correction phase across the array, which maintains the desired beam direction.
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