Antenna for a mobile station operating in two frequency ranges

• US 6,028,567 A
• Filed: 12/08/1998
• Issued: 02/22/2000
• Est. Priority Date: 12/10/1997
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Lahti, Saku
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Malos, Jennifer H.
• Application Number:
  US09/207,880
• Time in Patent Office: 441 Days
• Field of Search: 343/895, 343/700 MS, 343/702, 343/806
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• 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 5/371 Branching current paths
• 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 9/40 Element having extended radiating surface
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

The invention comprises an antenna structure particularly suitable for mobile stations operating on two frequency ranges. As a supporting component and also as component determining the electrical characteristics the antenna includes a dielectric plate (21). On one surface of the dielectric plate there is a radiating element (22) with a meander form, and on the opposite support of the dielectric plate there is a planar radiating element (23). The operation on two frequency ranges is based on the fact that the structure has two resonance frequencies, which are relatively far from each other. The strips are further relatively wide, due to which the antenna operates satisfactorily in different positions and in the vicinity of objects. The parasitic element can further have a gap operating as a separate radiator, whereby the antenna operates on three frequency ranges. The antenna according to the invention is flat, and therefore it can be fixed to the back wall of a mobile station, and the distance to the user'"'"'s head is as large as possible.

Claims

1. An antenna which comprises a first element connected to its feed line and at least one parasitic element characterized in that

said first element is a meander element,

said parasitic element is a planar conductor area, and

the supporting structure for the meander and parasitic elements is a dielectric plate, where said dielectric plate is the dielectric part of a printed circuit board, said meander element is a conductor area on the first surface of said printed circuit board and said parasitic element is a conductor area on the second, opposite surface of said printed circuit board, the antenna having a first operating frequency band and a second operating frequency band, the second operating frequency band being higher in frequency than the first operating frequency band, said parasitic element being adapted to widen at least the second operating frequency band.

2. A structure according to claim 1, characterised in that the width of the meander element in a first point in the height direction is different from its width in a second point in the height direction.

3. A structure according to claim 1, characterised in that the height of the parasitic element is less than the height of the meander element.

4. A structure according to claim 1, characterised in that the width of the parasitic element in a first point in the height direction is different from the width in a second point in the height direction.

5. A structure according to claim 1, characterised in that the parasitic element has a radiating gap.

6. A structure according to claim 1 which comprises a first parasitic element and a second parasitic element, characterised in that said second parasitic element is conductor area on the same side of the dielectric plate as the meander element.

7. A mobile station having an antenna structure which comprises a feed line, a first element connected to the feed line and at least one parasitic element, characterized in that

said first element is a meander element,

said parasitic element is a planar conductor area, and

in that the antenna structure further comprises a supporting structure for the meander and parasitic elements, which supporting structure is a dielectric plate, where said dielectric plate is the dielectric part of a printed circuit board, said meander element is a conductor area on the first surface of said printed circuit board and said parasitic element is a conductor area on the second, opposite surface of said printed circuit board, the antenna having a first operating frequency band and a second operating frequency band, the second operating frequency band being higher in frequency than the first operating frequency band, said parasitic element being adapted to widen at least the second operating frequency band.

8. An antenna having a feed line, a first element connected to the feed line, and at least one parasitic element characterized in that

said first element is a meander element,

said parasitic element is a planar conductor area, and

the width of the meander element at a first location in the height direction is different from its width at a second location in the height direction, and in that the antenna structure further comprises a supporting structure for the meander and parasitic elements, said supporting structure being a dielectric plate, where said dielectric plate is the dielectric part of a printed circuit board, said meander element is a conductor area on the first surface of said printed circuit board and said parasitic element is a conductor area on the second, opposite surface of said printed circuit board, the antenna having a first operating frequency band and a second operating frequency band, the second operating frequency band being higher in frequency than the first operating frequency band, said parasitic element being adapted to widen at least the second operating frequency band.