| 摘要 |
1,270,806. Aerials; pulse radar. EMI Ltd. 12 May, 1969 [31 May, 1968.] No. 26084/68. HeadingsH4A and H4D. Two interleaved aerial arrays produce respectively the sum 1, Fig. 1, and the difference 2, 3 patterns; there is no coupling between the arrays. In the embodiment one array consists of slotted waveguides 4, 5, 6, 7, Fig. 2, and the other of slotted waveguides 8, 9, 10, 11; the waveguides may be ridge waveguides. As applied to a radar the pulse transmitter is coupled to guides 4 ... 7. It is stated that there is no coupling between the arrays because the patterns are sum and difference types and are produced substantially by the same aperture. Lobe 2 output is in phase quadrature to the sum signal and lobe 3 output is of opposite phase to lobe 2, Unwanted grating lobes are reduced if the array interleaving is close. The output of detector 20 has a polarity representing the target direction off the sum signal axis and an amplitude representing the magnitude thereof. The output of detector 19 (which responds to the sum pattern only) may be used for ranging and automatic gain control. The output of detector 20 may be utilized to tilt the aerial system to follow the target in elevation, and to follow it in azimuth the lobes are shifted by altering phase in the waveguides; that output may also be utilized for producing a moving-target display from sideways-looking radar on an aircraft. |
