Com Dev Limited

Anthony R Raab

William Thorpe

Thomas P Healy

Henry Downs

An electronically scanned radar system has a serpentine antenna, with at least two ports. The antenna is physically rotated. Each port has a mixer, transmitter and local oscillator feeding signals to it, the signals of the transmitter and oscillator being synchronized with one another to take advantage of the physical rotation of the antenna. The radar system can be operated in various ways to produce two independent beams simultaneously in a surveillance mode and/or tracking mode at each port. Furthermore, with the use of coupling means, the system can be operated to produce four independent beams at two different frequencies simultaneously. The system can also be operated to produce one or more beams in a surveillance mode and/or one or more beams in a tracking mode at each port. Further, the system can be operated to compensate for the physical rotation of the antenna and can avoid jammers by hopping to another frequency.

Electronically scanned radar system

An electronically scanned radiometer has a dispersive serpentine antenna with one or two ports. A mixer is connected to each port with each mixer being fed by a variable frequency local oscillator. Each oscillator provides the mixer to which it is connected with a drive signal that varies in frequency. The antenna most efficiently receives one or more beams through radiators at an angle that varies with the frequency of the drive signal at the mixer. An output is received at each port and is appropriately displayed. When the serpentine has two ports the radiometer can be operated at two orthogonal polarizations. The frequency being fed to each mixer can be varied in various predetermined patterns. Scanning of the beam can be effected by changing the frequency of observation without physically rotating the antenna. Also two simultaneous beams rotating in opposite directions with independent motions can be achieved.

Frequency-scanning radiometer

A reconfigurable beam-forming network for use with a transmitter has a waveguide R-switch that is interconnected with a Magic T. The R-switch contains phasing elements and is connected to a dual-mode power-dividing network, which in turn is connected to first, second and third region power-dividing networks, each having their own feed horn array. The R-switch can be moved to three different positions so that in a first position power is divided between two input ports of the dual-mode network on substantially a fifty-fifty basis with the power on the two input ports being out of phase on a positive basis. In a second position of the R-switch, power is also divided on substantially a fifty-fifty basis between the two input ports but the power is out of phase between the two ports on a negative basis. In a third position of the R-switch, substantially all of the power entering the R-switch is passed into the first input port of the dual-mode network. The power being fed to the feed horns of any one of the regions has the same phase. In a variation of the invention, the R-switch and Magic T are replaced by a variable phase shifter and Magic T.

Reconfigurable beam-forming network that provides in-phase power to each

A Beam-forming Network includes a plurality of directional couplers and phase shifters and which can interconnect both a transmitter and a receiver to the same group of radiating elements of an antenna even though the transmitter frequency band is different and well spaced from the receiver frequency band. This is accomplished, in accordance with the invention, by using directional couplers each of which has a variable response over a wide band of frequencies but which is designed so that its response over the transmitter frequency band is stable and its response over the receiver frequency band is also stable.

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Waterloo, Canada

Anthony R Raab