Antenna device for portable equipment

• US 5,757,325 A
• Filed: 05/24/1995
• Issued: 05/26/1998
• Est. Priority Date: 10/29/1992
• Status: Expired due to Term

• Current Assignee: Laird Technologies AB (Laird PLC)
• Original Assignee: Allgon AB (Bure Equity AB)
• Inventors: Saldell, Ulf
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/331,530
• Time in Patent Office: 1,098 Days
• Field of Search: 343/702, 343/715, 343/745, 343/749, 343/860, 343/900, 343/901, 343/902
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/244 extendable from a housing along a given path
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

The antenna device of the present invention is intended for a portable equipment for transmitting and/or receiving radio signals. Said antenna device comprises a helical antenna substantially having the characteristics of a half-wave antenna, a half-wave antenna, and an impedance transformer. Said helical antenna, said half-wave antenna, and said impedance transformer are intercouplable so that either said helical antenna alone is coupled to said impedance transformer or said helical antenna and said half-wave antenna are coupled in parallel to said impedance transformer in order to form two different working functions.

Claims

1. In an apparatus which includes a helical antenna element disposed on a case of a radio circuit;

impedance transforming circuitry connected to said helical antenna element and to said radio circuit; and

an antenna element which can be accommodated in or extended outside of said case through said helical antenna element;

the improvement comprising said helical antenna element and said antenna element each having a one-half wave length, and connecting means for conductively and directly connecting said impedance transforming circuitry through a conductive coupler to said antenna element when said antenna element is extended so that said helical antenna element and said antenna element are conductively and directly connected in parallel with each other to said impedance transforming circuitry.

2. An apparatus according to claim 1 wherein said antenna element is a rod antenna.

3. An apparatus according to claim 1 wherein said conductive coupler includes a holder conductor portion supporting said helical antenna element, and said antenna element includes a conductive lower end portion, wherein when said antenna element is extended, said conductive lower end portion is engaged with said conductive coupler, said conductive coupler being connected with said radio circuit in said case through said impedance transforming circuitry.

4. An apparatus according to claim 3 further including an insulator covering said antenna element and having an extended portion which projects above an upper end portion of said antenna element.

5. An apparatus according to claim 4 wherein said extended portion is longer than a vertical height of said helical antenna element.

6. An apparatus comprising a helical antenna element disposed on a case of a radio circuit;

impedance transforming circuitry connected to said helical antenna element and to said radio circuit;

an elongated antenna element which can be supported for movement between a retracted position disposed substantially within said case and an extended position in which a portion extends outside of said case and moveable through said helical antenna element;

wherein said helical antenna element and said elongated antenna element are each of one-half wave-length; and

means electrically coupling said impedance transforming circuitry to said helical antenna element and respectively effecting and interrupting an electrical coupling of said impedance transforming circuitry to said elongated antenna element when said elongated antenna element is in its extended and retracted positions respectively, said means including a conductive holding means supported on said case and electrically coupled to said impedance transforming circuitry and said helical antenna element, said elongated antenna element being electrically and conductively and directly coupled to said conductive holding means and being free of electrical coupling to said conductive holding means when said elongated antenna element is respectively in said extended and retracted positions.

7. The apparatus as claimed in claim 6 wherein said helical antenna element provides the entire antenna function when said elongated antenna element is in its retracted position.

8. An apparatus according to claim 6 wherein said elongated antenna element includes an elongated insulator encasing said elongated antenna element and wherein said means includes a conductive portion at one end of said elongated antenna element and electrically integral with said elongated antenna element, said conductive portion respectively directly contacting and being axially spaced from said conductive holding means when said elongated antenna element is respectively in said extended and retracted positions.

9. An apparatus according to claim 8 including cooperating means on said conductive holding means and said conductive portion for preventing movement of said elongated antenna element beyond said extended position.

10. An apparatus according to claim 9 wherein said elongated insulator has at an outer end thereof an enlarged portion which is engagable with said case in said retracted portion for preventing movement of said elongated antenna element beyond said retracted position.

11. An apparatus according to claim 6 wherein said elongated antenna element includes a nonconductive end portion extending a predetermined distance outwardly beyond an outer end of said elongated antenna element, wherein said helical antenna element has a length less than said predetermined distance and wherein said end portion is within said helical antenna element when said elongated antenna element is in said retracted position.

12. In an apparatus which includes:

a helical antenna element disposed on a case of a radio circuit;

a matching circuit connected to said helical antenna element and to said radio circuit; and

a whip antenna element which can be accommodated in or extended outside of said case through said helical antenna element;

the improvement comprising said helical antenna element and said whip antenna element each having a 1/2-wave length, and connecting means for conductively and directly connecting said matching circuit through a conductive coupler to said whip antenna element when said whip antenna element is extended, so that said antenna elements are conductively and directly connected in parallel with each other to said matching circuit.

13. An apparatus according to claim 12, wherein said conductive coupler includes a holder conductor supporting said helical antenna element and includes a stopper conductor disposed on a lower end portion of said whip antenna element, wherein when said whip antenna element is extended, said stopper conductor is engaged with said holder conductor, said holder conductor being connected with said radio circuit in said case through said matching circuit.

14. An apparatus according to claim 13, further including an insulator covering said whip antenna element and having an extended portion which projects above an upper end portion of said whip antenna element and which is longer than a vertical height of said helical antenna.

15. An apparatus according to claim 12, further including an insulator covering said whip antenna elements and having an extended portion which projects above an upper end portion of said whip antenna element and which is longer than a vertical height of said helical antenna.

16. An apparatus, comprising:

a case, an elongate whip antenna having an elongate conductive whip element of 1/2-wave length and supported on said case for length-wise movement along an axis relative to said case between a retracted position disposed substantially within said case and an extended position in which a portion thereof projects outwardly from said case, a conductive helical antenna element of 1/2-wave length supported on said case so as to extend helically around said axis, said whip antenna extending through said helical antenna element, a radio circuit disposed in said case, a matching circuit disposed in said case and electrically coupled to said radio circuit, and means electrically coupling said matching circuit to said helical antenna element, and respectively effecting and interrupting an electrical coupling of said matching circuit to said whip element when said whip antenna is respectively in said extended and retracted positions, said means include a holder conductor supported on said case and electrically coupled to said matching circuit and said helical antenna element, said whip element being electrically and conductively and directly coupled to said holder conductor and being free of electrical coupling to said holder conductor when said whip antenna is respectively in said extended and retracted positions.

17. An apparatus, according to claim 16, wherein said whip antenna includes an elongate insulator having said whip element therein, and wherein said means includes a further conductor mounted on one end of said whip antenna and electrically connected to said whip element, said further conductor respectively directly contacting and being axially spaced from said holder conductor when said whip antenna is respectively in said extended and retracted positions.

18. An apparatus according to claim 17, including cooperating means on said holder conductor and further conductor for preventing movement of said whip antenna beyond said extended position.

19. An apparatus according to claim 18, wherein said insulator has at an outer end thereof an enlarged portion which is engagable with said case in said retracted position for preventing movement of said whip antenna beyond said retracted position.

20. An apparatus according to claim 16, wherein said whip antenna includes a nonconductive end portion extending a predetermined axial distance outwardly beyond an outer end of said whip element, wherein said helical antenna element has a dimension in a direction parallel to said axis which is less than said predetermined axial distance, and wherein said end portion of said whip antenna is substantially axially aligned with said helical antenna element when said whip antenna is in said retracted position.