Phased array radars
First Claim
1. A radar having a plurality of antennae, a plurality of receiving channels each associated with a respective antennae and including an amplifier and a first frequency mixer/generator, means for providing a reference signal of known frequency which is different from the radar carrier frequency to the input of each receiving channel, filter means in each receiving channel for separating the I.F. frequency corresponding to the reference signal from that corresponding to the signal induced in the antennae and a second frequency mixer for mixing the signals at the outputs of the filter means to generate a second intermediate frequency for utilisation by a beam forming network.
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Accused Products
Abstract
A phased array radar having a plurality of antennae, each connected with a respective receiving channel, is provided with apparatus to suppress variations in phase and gain in the receiving channels. The apparatus injects a reference signal into a normally provided head amplifier in each channel, which then passes through the same amplification and frequency changing circuits as the signal induced in each antennae. Thus the differential phase shifts of the reference signal and the radar carrier frequency are substantially constant. The gains of the head amplifiers are controlled by the action of an AGC loop.
19 Citations
7 Claims
- 1. A radar having a plurality of antennae, a plurality of receiving channels each associated with a respective antennae and including an amplifier and a first frequency mixer/generator, means for providing a reference signal of known frequency which is different from the radar carrier frequency to the input of each receiving channel, filter means in each receiving channel for separating the I.F. frequency corresponding to the reference signal from that corresponding to the signal induced in the antennae and a second frequency mixer for mixing the signals at the outputs of the filter means to generate a second intermediate frequency for utilisation by a beam forming network.
Specification