Antenna having a returned portion forming a portion arranged in parallel to the longitudinal antenna direction

• US 5,995,064 A
• Filed: 11/25/1996
• Issued: 11/30/1999
• Est. Priority Date: 06/20/1996
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Yokowa Also Trading As Yokowo Company Limited
• Original Assignee: Kabushiki Kaisha Yokowa Also Trading As Yokowo Company Limited
• Inventors: Sato, Atsushi, Kawahara, Takao, Arai, Michio, Yanagisawa, Wasuke, Horie, Ryo, Oshiyama, Tadashi, Yano, Takumi
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Ho, Tan
• Application Number:
  US08/755,733
• Time in Patent Office: 1,100 Days
• Field of Search: 343/702, 343/895, 343/715, 343/745, 343/749, 343/806, 343/900, 343/901
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/244 extendable from a housing along a given path
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 5/392 the parasitic elements having dual-band or multi-band characteristics
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

The antenna element (1) of a long conductor is formed with at least one returned portion (1a) arranged substantially in parallel to a longitudinal direction of the antenna element. In practice, a physical length of the antenna element in the longitudinal direction is determined to such a length as to be substantially resonated in a first frequency band, and the at least one returned portion (1a) is formed in such a way as to be resonated in a second frequency band twice higher than the first frequency band on the basis of an electric coupling with the adjacent antenna element. Further, the antenna can be constructed in such a way that: an antenna element (1) of a long conductor is formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element in such a way that an electrical length thereof is substantially 3/4 wavelength of a frequency band of transmitted and received signals; and at least half element (213) of an electrical length of substantially 1/4 wavelength of the frequency band beginning from an end portion of the antenna element on a side opposite to a feeder portion (30) side is formed as an extended antenna piece extending substantially in non-parallel to the substantially parallel-formed antenna elements (211, 212).

Claims

1. An antenna, wherein an antenna element formed by a long conductor is formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element,

wherein the long conductor and the returned portion are adjacent to one another and where a physical length of the antenna element in the longitudinal direction is determined to such a length so as to be substantially resonated in a first frequency band, and the at least one returned portion is formed so as to enable the antenna to transmit and receive signals of said first frequency band and a second frequency band, wherein the second frequency band is approximately an even number times higher than the first frequency band.

2. The antenna of claim 1, wherein the long conductor is formed by a belt-shaped body.

3. The antenna of claim 1, wherein the long conductor and the returned portion are adjacent to one another and where the antenna element formed with the returned portion is wound into a coil shape with the longitudinal direction of the antenna element as a central axis thereof so as to maintain electrical coupling with the adjacent antenna element.

4. The antenna of claim 1, wherein the long conductor is formed into a zigzag shape and formed with the returned portion in such a way that zigzag portions thereof are adjacent to each other.

5. The antenna of claim 1, wherein the length of the long conductor in the longitudinal direction is formed so as to correspond to substantially 1/4 wavelength of the first frequency band.

6. The antenna attached to a radio apparatus, comprising:

a first antenna portion having one end connected to a feeder portion and defined by claim 1; and

a second antenna portion separated from the feeder portion when housed in a casing of the radio apparatus, and having one end coupled electrically to the other end of the first antenna portion when extended externally from the casing of the radio apparatus.

7. The antenna of claim 6, wherein the other end of the first antenna portion and one end of the second antenna portion are electrically coupled capacitively and/or inductively, without direct contact between the two antenna portions.

8. The antenna, comprising:

a first antenna portion having a metal fixture connected to a feeder portion at a lower end portion thereof and defined as claim 1; and

a second antenna portion separated from the feeder portion when housed in a casing of a radio apparatus and having a stopper portion disposed at a lower end thereof and connected to the feeder portion when extended externally from the casing of the radio apparatus, the metal fixture of the first antenna portion being fixed to an upper end portion of the extended second antenna portion.

9. The antenna of claim 8, wherein the first antenna portion and the second antenna portion are connected to each other electrically.

10. The antenna of claim 8, wherein the first antenna portion and the second antenna portion are coupled to each other capacitively and/or inductively.

11. The antenna of claim 8, wherein the second antenna portion is constructed by the antenna as defined by claim 1.

12. The radio apparatus, comprising:

a transmit and receive circuit;

a casing for covering the transmit and receive circuit;

a feeder portion disposed in the vicinity of the casing and electrically connected to the transmit and receive circuit; and

an antenna attached to the casing and electrically connected to the feeder portion, the antenna as defined by claim 2 being used as at least a part of the antenna of the radio apparatus.

13. The antenna of claim 2, wherein the first frequency band includes the frequency 900 MHz and the second frequency band includes the frequency 1800 MHz.

14. An antenna, comprising:

a first antenna portion having an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element, the first antenna portion being formed in such a way that a total electrical length thereof is substantially 1/4 wavelength of a first frequency band but substantially 3/4 wavelength of a second frequency band; and

a second antenna portion having one end portion connected electrically to the first antenna portion when extended externally from a casing, the second antenna portion being composed of a first antenna element formed in such a way that an electrical length thereof is substantially 1/2 wavelength of the second frequency band and a second antenna element connected to the first antenna element electrically and formed in such a way that a total electrical length together with the first antenna element is substantially 1/2 wavelength of the first frequency band.

15. The antenna of claim 14, wherein the first antenna element and the second antenna element are connected to each other via a trap parallel-resonated in the second frequency band.

16. The antenna of claim 14, wherein the first antenna element and the second antenna element are connected to each other via a phase shifter for shifting a phase of 180 degrees with respect to the second frequency band.

17. The antenna of claim 14, wherein the first antenna portion is formed with a coupling returned portion at a position an electrical length of substantially 1/4 wavelength of the second frequency band away from one end portion thereof on feeder portion side, and further the second antenna portion is so disposed as to be coupled capacitively and/or inductively with both the coupling returned portion and the other end of the first antenna portion.

18. An antenna, wherein a second antenna portion formed so as to have an electrical length of substantially 1/2 wavelength of one frequency band is connected electrically, when extended, to a first antenna portion formed in such a way a total length thereof has an electrical length of substantially 3/4 wavelength of the one frequency band;

and, the first antenna portion is formed in such a way that a portion corresponding to an electrical length of substantially 1/2 wavelength of the frequency band functions as a phase shifter for canceling electric fields with each other.

19. An antenna, comprising:

a first antenna portion having an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element; and

a second antenna portion having one end portion connected electrically to the first antenna portion when extended externally from a casing, the second antenna portion being a series resonance circuit having an inductor element and a capacitor element and coupled with the first antenna portion capacitively and/or inductively.

20. The antenna of claim 19, wherein the first antenna portion is formed with the returned portion for transmitting and receiving both first and second frequency bands, respectively;

the second antenna portion is composed of a first series resonance circuit series-resonated in the first frequency band and a second series resonance circuit series-resonated in the second frequency band; and

the first and second series resonance circuits are coupled with each other capacitively and/or inductively.

21. An antenna, comprising:

an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element in such a way that an electrical length thereof is substantially 3/4 wavelength of a frequency band of transmitted and received signals; and

at least half of an electrical length of substantially 1/4 wavelength of the frequency band beginning from an end portion of the antenna element on a side opposite to a feeder portion side is formed as an extended antenna piece extending substantially in non-parallel to the substantially parallel-formed antenna element.

22. The antenna of claim 21, wherein the at least half of the electrical length of substantially 1/4 wavelength portion extending substantially in non-parallel is extended in such a way that small crank-shaped portions are repeatedly formed along the substantially parallel-formed antenna element.

23. An antenna, comprising:

an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element in such a way that an electrical length thereof is substantially 1/4 wavelength of a first frequency band; and

a coupling returned portion formed so as to be coupled with a second antenna portion capacitively and/or inductively at a position an electrical length of substantially 1/4 wavelength of a second frequency band away from a feeder portion side of the antenna element.

24. The antenna, comprising:

a first antenna portion as defined by claim 23 and formed by an antenna element disposed on an outer circumferential portion of a cylindrical insulating body;

a second antenna portion coupled with the first antenna portion capacitively and/or inductively when extended externally being slidably moved along an inner circumferential portion of the insulating body; and

the end portion of the antenna element of the first antenna portion being formed at a position farther away from the second antenna portion than the coupling returned portion in such a way that the second antenna portion can be easily coupled with the coupling returned portion of the first antenna portion in the second frequency band at an end portion opposite to a feeder portion of the antenna element of the first antenna portion.

25. An antenna, comprising:

a cylindrical core fixed to a metal fixture at one end thereof;

a ring spring disposed coaxially with the core on the other end portion of the core;

a cap formed with a through hole communicating with a central hole of the core and covering the core and the ring spring; and

a rod antenna member formed with a large-diameter top portion and a joint portion on both ends thereof so as to be slidably fitted to the central hole of the core,

wherein a notch engaged with the ring spring is formed at the top portion and the joint portion of the rod antenna member, respectively.

26. The antenna of claim 25, wherein a split-type stopper having an outer diameter larger an inner diameter of a hole of the cylindrical core, through which the joint portion of the rod antenna member is slidably moved, is fitted to an end portion of the joint portion of the rod antenna member.

27. The antenna of claim 25, wherein the cylindrical core is formed of an electrically insulating substance, and a first antenna portion is formed by disposing an antenna element on an outer circumference of the core.

28. A radio apparatus, comprising:

a high frequency circuit board disposed in a casing; and

,

an antenna formed with an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element, the antenna being provided on the high frequency circuit board,

wherein the long conductor and the returned portion are adjacent to one another and where a physical length of the antenna element in the longitudinal direction is determined to such a length so as to be substantially resonated in a first frequency band, and the at least one returned portion is formed so as to enable the antenna to transmit and receive signals of said first frequency band and a second frequency band, wherein the second frequency band is approximately an even number times higher than the first frequency band.

29. A radio apparatus, comprising:

a high frequency circuit board disposed in a casing; and

an antenna element formed by a long conductor and formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element in such a way that an electrical length thereof is substantially 3/4 wavelength of a frequency band of transmitted and received signals; and

at least half of an electrical length of substantially 1/4 wavelength of the frequency band beginning from an end portion of the antenna element on a side opposite to a feeder portion side is formed as an extended antenna piece extending substantially in non-parallel to the substantially parallel-formed antenna element, the antenna being provided on the high frequency circuit board.

30. An antenna attached to a radio apparatus comprising:

a first antenna portion wherein an antenna element formed by a long conductor is formed with at least one returned portion arranged substantially in parallel to a longitudinal direction of the antenna element, one end of said first antenna portion connected to a feeder portion; and

,

a second antenna portion separated from the feeder portion when housed in a casing of the radio apparatus, and having one end coupled electrically to the other end of the first antenna portion when extended externally from the casing of the radio apparatus,

wherein the antenna element is formed by an electrically conductive belt-shaped body disposed on an outer circumference of a cylindrical bobbin formed of an electrically insulating substance.

31. The antenna of claim 30, wherein one end of the first antenna element is electrically connected to a metal fixture for mounting a feeder disposed at a lower portion of the first antenna portion;

and the other end of the first antenna element is formed with a projection portion projecting radially inward of the bobbin via a through hole formed at a part of a side wall of the bobbin; and

the first and second antenna portions are connected electrically by fitting the projection portion to a recessed portion formed in a metal stopper attached to a lower end of the second antenna portion in electrical contact with the second antenna element.