Abstract A parallel-plate feed system for a circular array antenna is disclosed. The feed system comprises a parallel-plate region which places the correct phases at the array radiating elements when the parallel-plate region and the array radii are in a 1:2 ratio. Positioned about the periphery of the region are a plurality of input-output ports or probes. A plurality of adjacent input ports are fed simultaneously with a tapered amplitude distribution. By feeding more than one of the input probes simultaneously, the energy propagated through the parallel-plate region is highly directive, and the amplitude distribution obtained at the output probes has a considerable taper. By applying the resulting amplitude distribution to a sector of the circular array with the proper phase from the region low sidelobe patterns can be obtained. The beam is scanned in azimuth by means of diode switches at each lens port and by additional circuitry to maintain the proper input-probe taper. The system is operable over a 20 percent frequency band.
A parallel-plate feed system for a circular-array antenna comprising: a. sending apparatus; b. power divider means connected to said sending apparatus; c. a parallel-plate region consisting of two circular, metal plates of radius R spaced in parallel relationship to each other; d. a plurality of ports equispaced and supported substantially about the circumference of said parallel-plate region; e. means connected between the output of said power divider means and the inputs of said ports for providing a tapered amplitude distribution simultaneously to a predetermined number of adjacent ports; f. a circular-array antenna of radius 2R consisting of 2N radiating elements equispaced substantially about the circumference of said circular array, wherein N equals the number of said ports; and g. equal-length cables connected between the output of each of said ports and the inputs of two diametrically opposite radiating elements.
Claim 2
Dependent Claim
139 words
A parallel-plate feed system for a circular-array antenna comprising: a. sending apparatus; b. power divider means connected to said sending apparatus; c. a parallel-plate region consisting of two circular, metal plates of radius R spaced in parallel relationship to each other; d. a plurality of ports equispaced and supported substantially about the circumference of said parallel-plate region; e. means connected between the output of said power divider means and the inputs of said ports for providing a tapered amplitude distribution simultaneously to a predetermined number of adjacent ports; f. a circular-array antenna of radius 2R consisting of 2N radiating elements equispaced substantially about the circumference of said circular array, wherein N equals the number of said ports; and g. equal-length cables connected between the output of each of said ports and the inputs of two diametrically opposite radiating elements.
Claim 3
Dependent Claim
10 words
The parallel-plate feed system of claim 1 wherein N 64.
Claim 4
Dependent Claim
24 words
The parallel-plate feed system of claim 2 wherein said radius R is approximately equal to 13 lambda /2, where lambda is a free-space wavelength.
Claim 5
Dependent Claim
20 words
The parallel-plate feed system of claim 3 wherein said metal plates are spaced less than lambda /2 between each other.