Switched rhombic automatic direction finding antenna system and apparatus

Claim 2

A rhombic antenna array having feed and terminating points for use in a selected frequency band comprising: first, second, third, and fourth elements having dimensions that are a small fraction of the smallest wavelength in the selected frequency band, said first, second, third, and fourth elements each comprising helically wound conductor members on ferrite cores, tuning network means coupled to said first, second, third, and fourth elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, said tuning network means comprising a first varactor diode and first and second capacitors connected in series between said first and second elements.

Claim 3

A rhombic antenna array having feed and terminating points for use in a selected frequency band comprising: first, second, third, and fourth elements having dimensions that are a small fraction of the smallest wavelength in the selected frequency band, said first, second, third, and fourth elements each comprising helically wound conductor members on ferrite cores, tuning network means coupled to said first, second, third, and fourth elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, said tuning network means comprising a first varactor diode and first and second capacitors connected in series between said first and second elements, said tuning network means further comprising a second varactor diode and third and fourth capacitors connected in series between said third and fourth elements.

Claim 4

A rhombic antenna array having feed and terminating points for use in a selected frequency band comprising: first, second, third, and fourth elements having dimensions that are a small fraction of the smallest wavelength in the selected frequency band, said first, second, third, and fourth elements each comprising helically wound conductor members on ferrite cores, tuning network means coupled to said first, second, third, and fourth elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, said tuning network means comprising a first varactor diode and first and second capacitors connected in series between said first and second elements, said tuning network means further comprising a second varactor diode and third and fourth capacitors connected in series between said third and fourth elements.

Claim 5

In an automatic direction finding system, the combination of: an automatic direction finder receiver, a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to said rhombic antenna, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, differential capacitor means coupled between said lobe switching means and said automatic direction finding receiver, said differential capacitor having first and second stator plates coupled respectively to said feed and terminating points of said four element rhombic antenna, and a rotor plate, said automatic direction finder receiver comprising signal processing means including signal amplifier and phase detector means coupled to said rotor plate for developing servo control for controlled movement of said differential capacitor rotor.

Claim 6

In an automatic direction finding system, the combination of: an automatic direction finder receiver, a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to said rhombic antenna, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, differential capacitor means coupled between said lobe switching means and said automatic direction finding receiver, said differential capacitor having first and second stator plates coupled respectively to said feed and terminating points of said four element rhombic antenna, and a rotor plate, said automatic direction finder receiver comprising signal processing means including signal amplifier and phase detector means coupled to said rotor plate for developing servo control for controlled movement of said differential capacitor rotor.

Claim 7

A rhombic antenna array having feed and terminating points for coupling to a variable frequency receiver providing a tuning voltage having an amplitude which varies with the frequency to which the receiver is tuned comprising: first, second, third, and fourth elements having dimensions that are a small fraction of the smallest wavelength in the selected frequency band, said first, second, third, and fourth elements each comprising helically wound conductor members on ferrite cores, tuning network means coupled to said first, second, third, And fourth elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, said tuning network means comprising variable voltage capacitor means responsive to said tuning voltage for achieving and maintaining said substantially resonant condition with changes in frequency of said receiver.

Claim 8

A rhombic antenna array having feed and terminating points for coupling to a variable frequency receiver providing a tuning voltage having an amplitude which varies with the frequency to which the receiver is tuned comprising: first, second, third, and fourth elements having dimensions that are a small fraction of the smallest wavelength in the selected frequency band, said first, second, third, and fourth elements each comprising helically wound conductor members on ferrite cores, tuning network means coupled to said first, second, third, And fourth elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, said tuning network means comprising variable voltage capacitor means responsive to said tuning voltage for achieving and maintaining said substantially resonant condition with changes in frequency of said receiver.

Claim 9

In an automatic direction finding system, the combination of: a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to each of said four elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver and means including a servo driven capacitor rotor shaft coupled between said lobe switching network means and said automatic direction finding receiver for providing bearing information dependent upon said shaft position.

Claim 10

In an automatic direction finding system, the combination of: a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to each of said four elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver and means including a servo driven capacitor rotor shaft coupled between said lobe switching network means and said automatic direction finding receiver for providing bearing information dependent upon said shaft position.

Claim 11

In an automatic direction finding system, the combination of: a four element rhombic antenna for providing a cardioid type pattern and having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to each of said four elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver, and differential capacitor means for coupling signal voltages derived from lobe switching to said receiver.

Claim 12

In an automatic direction finding system, the combination of: a four element rhombic antenna for providing a cardioid type pattern and having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, tuning network means coupled to each of said four elements for tuning said antenna to a substantially resonant condition between said feed and terminating points, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver, and differential capacitor means for coupling signal voltages derived from lobe switching to said receiver.

Claim 13

In combination: a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver comprising signal amplifier and phase detector means, and differential capacitor means comprising first and second stator terminals and a rotor, said lobe switching means coupling the feed point to said first or second stator terminals, and said rotor coupled to said signal amplifier and phase detector.

Claim 14

In combination: a four element rhombic antenna having feed and terminating points, each of said elements comprising helically wound conductor members on ferrite cores, lobe switching network means operating to periodically interchange the feed and terminating points of the antenna, an automatic direction finder receiver comprising signal amplifier and phase detector means, and differential capacitor means comprising first and second stator terminals and a rotor, said lobe switching means coupling the feed point to said first or second stator terminals, and said rotor coupled to said signal amplifier and phase detector.

Claim 15

An automatic direction finder receiver antenna for mounting on the surface of an aircraft comprising: a four element rhombic antenna array, each of said elements comprising helically wound conductor members on ferrite cores, voltage controlled tuning means including first capacitor means for tuning two of said elements to resonance and second capacitor means for tuning the remaining two of said elements to resonance.

Claim 16

An automatic direction finder receiver antenna for mounting on the surface of an aircraft comprising: a four element rhombic antenna array, each of said elements comprising helically wound conductor members on ferrite cores, voltage controlled tuning means including first capacitor means for tuning two of said elements to resonance and second capacitor means for tuning the remaining two of said elements to resonance.