PRINTED CIRCUIT INDUCTIVE LOOP ANTENNA

• US 3,641,576 A
• Filed: 04/13/1970
• Issued: 02/08/1972
• Est. Priority Date: 04/13/1970
• Status: Expired due to Term

• Current Assignee: Walter Farbanish
• Original Assignee: Walter Farbanish
• Inventors: Farbanish, Walter
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/027,562
• Time in Patent Office: 666 Days
• Field of Search: 343/705,708,741,743,744,748,908,862
• US Class Current: 343/743
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142

Abstract

A relatively high-impedance FM radio antenna is provided consisting essentially of a circular loop of conductive foil having a discontinuity therein and deposited on one side of a substantially planar, nonconductive substrate. Attached to one end of the loop is a conductive foil impedance element, such as an inductor, for providing impedance matching in order to efficiently transfer the received electrical signals from the high-impedance antenna to a relatively low-impedance radio input circuit. A conductive foil capacitance element is connected between the impedance-matching element and the other end of the loop in order to parallel tune the antenna to the FM radio signal band. The capacitance is formed by depositing spaced interdigitated elongated strips of conductive foil on the substrate, with successive strips alternately attached to the loop end and to the impedance-matching element.

Claims

1. A high-impedance printed circuit antenna for receiving radio signals within a predetermined frequency band and converting them into corresponding electrical signals for application to a relatively low-impedance radio input circuit, comprising:

means including a substantially planar nonconductive substrate for supporting said antenna;

inductance means, including a loop of conductive foil having a discontinuity therein and deposited on said substrate, for receiving said radio signals and converting them into said electrical signals;

impedance-matching means, including a conductive foil impedance element deposited on said substrate and connected to said inductance means, for transferring said electrical signaLs from said high-impedance antenna to said relatively low-impedance input circuit with maximum efficiency; and

capacitance means connected to said inductance means and said matching means for broadly tuning said antenna to said frequency band, said capacitance means including a plurality of spaced interdigitated elongated strips of conductive foil deposited on said substrate and having successive strips alternately connected to said inductance means and to said matching means.

2. An antenna according to claim 1, in which said impedance-matching means further includes a balanced transmission line having an impedance substantially equal to said input impedance and connected between said impedance element and said input circuit.

3. An antenna according to claim 1, in which said impedance element comprises a printed circuit inductance connected in phase opposition to said inductance means.

4. An antenna according to claim 1, which further comprises an additional portion of conductive foil connected to said loop for reducing the value of said inductance means and reducing the Q of the antenna.

5. An antenna according to claim 1, in which said inductance means is a substantially circular loop, having an outside diameter of approximately 5 inches and a foil width of approximately one-half inch.