Automatic antenna coupler utilizing system for measuring the real part of the complex impedance or admittance presented by an antenna or other network

• US 3,919,644 A
• Filed: 02/18/1972
• Issued: 11/11/1975
• Est. Priority Date: 02/02/1970
• Status: Expired due to Term

• Current Assignee: Carl M. Smolka
• Original Assignee: Carl M. Smolka
• Inventors: Smolka, Carl M.
• Primary Examiner(s): Mayer, Albert J.
• Application Number:
  US05/229,215
• Time in Patent Office: 1,362 Days
• Field of Search: 325/171-179 333/17
• US Class Current: 455/123
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H03J 3/185 with varactors, i.e. voltage variable reactive diodes

Abstract

An automatic antenna coupler is described which includes a matching network having adjustable reactive elements. Control for these elements is provided by a system for detecting the real part of the complex impedance presented by the antenna or matching network. A logic and control system for adjusting the reactive elements is operated in accordance with the real part detector output so as to provide the desired impedance match.

Claims

1. A system for transforming the complex load which has electrical impedance and admittance characteristics presented by an electronic signal untilization device which receives signals, which system comprises:

an adjustable reactive element connected to said electronic signal utilization device and forming part of said load;

detection means response to the signals applied to said device for providing an error signal having a magnitude corresponding to the magnitude of the real part of one of said admittance and impedance of said load; and

means responsive to said error signal for adjusting said element until said error signal reaches a predetermined magnitude.

2. The invention as set forth in claim 1 wherein said system further comprises another adjustable reactive element, said elements being respectively connected in series and in shunt with said device and forming parts of said load, means included in said detection means for alternatively providing said error signal with magnitudes corresponding to the real part of the impedance and the real part of the admittance presented by said load, and means included in said error signal responsive means for independently adjusting said elements, one in response to said impedance real part corresponding error signal magnitude until the magnitude of said impedance real part error signal is of a predetermined magnitude and the other in response to said admittance real part corresponding error signal magnitude until the magnitude of said last named error signal is of a predetermined magnitude.

3. The invention as set forth in claim 2 wherein said device is an antenna and said reactive elements are an inductor connected in shunt and a capacitor in series with said antenna.

4. The invention as set forth in claim 1 including a second adjustable reactive elememt, said first mentioned element being connected in series with said device and said second element in shunt with said device, means responsive to signals reflected from said device for providing a second error signal having a magnitude corresponding to the other of said admittance and impedance of said load, and means included in said error signal responsive means for adjusting one of said first and second elements in response to one of said first and second error signal magnitudes and the other of said first and second elements in response to the other of said first named and second error signal mangitudes.

5. The invention as set forth in claim 4 wherein said reflected signal responsive means is a VSWR detector.

6. The invention as set forth in claim 1 wherein said detection means includes first and second channels, said first channel including means responsive to the voltage and current of said signals for providing a third output proportional to the amplitude of the component of said current which is in phase with said voltage, said second channel including means for providing a fourth output proportional to the amplitude of said voltage, means output responsive to said third and fourth outputs for providing a fifth output proportional to the ratio thereof.

7. The invention as set forth in claim 6 including means for comparing said fifth outout with a reference signal to provide the difference therebetween as said error signal.

8. The invention as set forth in claim 6 wherein said means included in said first channel is a balanced mixer circuit.

9. The invention as set forth in claim 6 wherein said means included in said second channel is an amplitude detector.

10. The invention as set forth in claim 6 wherein said fifth output providing means includes separate logarithmic amplifiers in said first and second channels respectively responsive to said third and fourth outputs, and means for providing the difference between the amplitudes of said third and fourth outputs to provide said fifth output.

11. A system for tuning a matching network to which signals are applied having a tuning element which comprises:

a. means for providing a first control signal having a characteristic, which is a function of the real part of the impedance to be matched by said network, b. means for providing a second control signal having a characteristic which is a function of the real part of the admittance to be matched by said network, c. control means for adjusting said tuning element, and d. means for alternatively applying said first and second control signals to said control means so that said network alternatively matches the real part of said impedance to be matched and said real part of said admittance to be matched.

12. The invention as set froth in claim 11 including means for connecting said matching network input to a radio transmitter, and means for connecting said matching network output to an antenna.