Antenna with P.I.N. diode switched tuning inductors

• US 4,564,843 A
• Filed: 12/01/1981
• Issued: 01/14/1986
• Est. Priority Date: 06/18/1981
• Status: Expired due to Term

• Current Assignee: Chelton (Electrostatics) Ltd. (Chelton Ltd.)
• Original Assignee: Charles E. Cooper
• Inventors: Cooper, Charles E.
• Primary Examiner(s): Lieberman, Eli
• Assistant Examiner(s): Wimer, Michael C.
• Application Number:
  US06/326,426
• Time in Patent Office: 1,505 Days
• Field of Search: 343/750, 343/749, 343/895, 343/876, 343/745, 343/747, 343/802, 455/121, 455/123, 455/193, 455/129, 455/120
• US Class Current: 343/745
• CPC Class Codes: H03J 5/246 using electronic means H03J5/244 takes precedence

Abstract

A tuned radio antenna for a frequency agile communication system has a plurality of tuning inductors in series with a short-circuiting switch for each inductor, each switch being formed by a pair or a plurality of pairs of P.I.N. diodes, control means being provided for applying biasing potentials to the diodes to effect switching of the antenna tuning.

Claims

1. A radio antenna for frequency agile operation at a plurality of frequencies in a predetermined frequency band, comprising:

a capacitive radiating/receiving element;

a plurality of discrete tuning inductors coupled in series with said radiating/receiving element, said inductors having different inductances and having a short-circuiting switch, each said short-circuiting switch including at least two P.I.N. diodes arranged for switchably short-circuiting at least a part of the respective inductor;

controller means coupled to said switches, for sequentially changing the tuning of the antenna by selectively applying a forward bias to said diodes to be maintained conductive and a reverse bias to said diodes to be maintained non-conductive; and

at least one of said inductors being divided into a plurality of parts having separate switches for each of said parts.

2. An antenna according to claim 1, wherein a capacitance is associated with each said switch tending to maintain an applied bias on each said switch.

3. A radio antenna for frequency agile operation at a plurality of frequencies in a predetermined frequency band, comprising:

a capacitive radiating/receiving element;

a plurality of discrete tuning inductors coupled in series with said radiating/receiving element, said inductors having different inductances and having a short-circuiting switch, each said short-circuiting switch including at least two P.I.N. diodes arranged for switchably short-circuiting at least a part of the respective inductor;

controller means coupled to said switches, for sequentially changing the tuning of the antenna by selectively applying a forward bias to said diodes to be maintained conductive and a reverse bias to said diodes to be maintained non-conductive; and

said inductor inductances increasing in steps with each successive inductor having an inductance substantially twice that of the next smaller inductor.

4. An antenna according to claim 3, wherein a capacitance is associated with each said switch tending to maintain an applied bias on each said switch.

5. A radio antenna for frequency agile operation at a plurality of frequencies in a predetermined frequency band, comprising:

a capacitive radiating/receiving element;

a plurality of discrete tuning inductors coupled in series with said radiating/receiving element, said inductors having different inductances and having a short-circuiting switch, each said short-circuiting switch including at least two P.I.N. diodes arranged for switchably short-circuiting at least a part of the respective inductor;

controller means coupled to said switches, for sequentially changing the tuning of the antenna by selectively applying a forward bias to said diodes to be maintained conductive and a reverse bias to said diodes to be maintained non-conductive; and

said diodes for each of said discrete inductors being connected back-to-back with a common junction therebetween and having a charge storage capacity; and

wherein said controller means is coupled for applying a biasing current to said common junctions for forward biasing of each said switches, said biasing current having a magnitude such that said charge storage capacity of each said diode holds each said diode conductive throughout a cycle of any radio frequency within the predetermined frequency band.

6. An antenna according to claim 5, wherein a capacitance is associated with each said switch tending to maintain an applied bias on each said switch.

7. A radio antenna for frequency agile operation at a plurality of frequencies in a predetermined frequency band, comprising:

a capacitive radiating/receiving element;

a plurality of discrete tuning inductors coupled in series with said radiating/receiving element, said inductors having different inductances and having a short-circuiting switch, each said short-circuiting switch including at least two P.I.N. diodes arranged for switchably short-circuiting at least a part of the respective inductor;

controller means coupled to said switches, for sequentially changing the tuning of the antenna by selectively applying a forward bias to said diodes to be maintained conductive and a reverse bias to said diodes to be maintained non-conductive;

wherein said switch for at least one of said discrete inductors comprises two groups of said P.I.N. diodes arranged for simultaneously switchably short circuiting respective parts of the inductor, each of said groups including two P.I.N. diodes connected back-to-back with a common junction therebetween, each of said diodes having a charge storage capacity; and

wherein said controller means is coupled for applying a biasing current to said common junctions for forward biasing of each said switch;

said biasing current having a magnitude such that said charge storage capacity of each said diode holds each said diode conductive throughout a cycle of any radio frequency within the predetermined frequency band.

8. An antenna according to claim 7, wherein a capacitance is associated with each said switch tending to maintain an applied bias on each said switch.