Electronic technique for an all-electronic cylindrical array beacon antenna

Claim 2

Apparatus for generating composite modulAted radio-frequency signals for energizing each column of radiators in a cylindrical antenna array, comprising: a first modulator for modulating a first fraction of the power from a source of radio-frequency energy with a first modulation frequency; a second modulator for modulating a second fraction of the power from a source of radio-frequency energy with a second modulation frequency which is an integral multiple of said first modulation frequency; phase shift means responsive to the energy modulated by said second modulator for shifting the phase of the radio-frequency power therefrom; and means for combining the outputs of said first modulator and said phase shifted output of said second modulator for producing a discrete composite excitation signal for a corresponding one of said columns of radiators.

Claim 3

In an inertialess antenna scanning system including a cylindrical array and a plurality f radiating elements arranged in columns distributed in juxtaposition around at least a portion of the circumference of said cylindrical array, said columns being arranged to be individually excited with radio-frequency energy modulated by a plurality of predetermined modulation signals at predetermined modulation signal phase for each of said columns to produce a radiation pattern equivalent to that which would result from rotation of said cylindrical array about its axis, the combination associated with each of said columns comprising: means for producing said plurality of modulation signals in the form of at least first and second synchronously generated modulating signals, said second modulation signal having a frequency equal to the product of said first modulation signal frequency and a constant greater than unity; means for dividing said radio-frequency energy into a plurality of paths; first modulating means within a first one of said radio-frequency energy paths for modulating the energy therein with said first modulation signal; second modulating means connected within a second one of said radio-frequency paths for modulating the energy therein with said second modulation signal; phase shift means connected within said second radio-frequency path for introducing a predetermined phase shift of said radio-frequency energy in said second path; and means for combining the output energies from said paths, thereby to provide a composite column excitation signal.

Claim 4

In an inertialess antenna scanning system including a cylindrical array and a plurality f radiating elements arranged in columns distributed in juxtaposition around at least a portion of the circumference of said cylindrical array, said columns being arranged to be individually excited with radio-frequency energy modulated by a plurality of predetermined modulation signals at predetermined modulation signal phase for each of said columns to produce a radiation pattern equivalent to that which would result from rotation of said cylindrical array about its axis, the combination associated with each of said columns comprising: means for producing said plurality of modulation signals in the form of at least first and second synchronously generated modulating signals, said second modulation signal having a frequency equal to the product of said first modulation signal frequency and a constant greater than unity; means for dividing said radio-frequency energy into a plurality of paths; first modulating means within a first one of said radio-frequency energy paths for modulating the energy therein with said first modulation signal; second modulating means connected within a second one of said radio-frequency paths for modulating the energy therein with said second modulation signal; phase shift means connected within said second radio-frequency path for introducing a predetermined phase shift of said radio-frequency energy in said second path; and means for combining the output energies from said paths, thereby to provide a composite column excitation signal.

Claim 5

The invention set forth in claim 2 in which said cylindrical array is oriented such that its axis is substantially vertical.

Claim 6

The invention set forth in claim 2 in which said second modulation signal frequency is defined as being an odd multiple greater than unity of the frequency of said first modulation signal.

Claim 7

The invention set forth in claim 2 in which said first modulation signal frequency is in the low sub-audio region, and said second modulation signal frequency is the ninth harmonic of said first signal.

Claim 8

The invention set forth in claim 5 further defined in that said modulation signals are predetermined to amplitudes such that said composite column excitation signal is modulated less than 100 percent at all times.

Claim 9

The invention set forth in claim 6 further defined in that said phase shift means in said second path is inserted after said second modulation means within the circuit of said second path.

Claim 10

The invention defined in claim 5 in which said means for dividing said radio-frequency energy comprises a separate directional coupler for coupling from a radio-frequency source into said first and second paths, and said means for combining the output energies from said paths comprises an additional separate directional coupler from the output of each of said first and second paths to form an output for said composite column excitation signal.

Claim 11

The invention defined in claim 8 in which said first and second modulation signals are 15 and 135 Hz, respectively.

Claim 12

The invention set forth in claim 7 in which said phase shift means in said second path introduces 45* of carrier phase shift measured at a predetermined radio frequency within the operating range of said antenna scanning system.