Antenna with variable directional pattern

• US 20030189523A1
• Filed: 04/04/2003
• Published: 10/09/2003
• Est. Priority Date: 04/09/2002
• Status: Active Grant

• Current Assignee: Cantor Fitzgerald Securities (Cantor Fitzgerald, L.P.)
• Original Assignee: Filtronic LK Oy
• Inventors: Ojantakanen, Seppo, Leppaluoto, Timo
• Granted Patent: US 6,967,618 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/245 with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements

Abstract

An antenna of a radio apparatus, the directional pattern of which can be altered controllably. The antenna comprises at least one conductive element, additional from the viewpoint of the basic operation of the antenna, for shaping the directional pattern of the antenna. Such a conductive element (330, 340) is connected to signal ground at a ground point relatively near the feed point (F) of the antenna. The conductive element has a part (331) the length of which is about a quarter of the wavelength at an operating frequency of the antenna, pointing from the ground point (G) in a direction substantially opposite to the feeding direction of the radiating element (320). That part is used to equalize the directional pattern of the antenna in the receiving band. In addition, the conductive element has a second part (332) pointing from the ground point to the feeding direction of the radiating element to set a directional pattern notch at transmitting band frequencies in a desired direction.

Claims

1. An antenna of a radio apparatus with a directional pattern that can be shaped and a radiating element and a feed conductor thereof connected to the radio apparatus at a feed point, wherein, for shaping the directional pattern of the antenna this additionally comprises at least one conductive element internal to the radio apparatus connected to signal ground in the radio apparatus at a ground point located relatively close to said feed point.

2. The antenna according to claim 1, wherein the conductive element comprises a part pointing from the ground point in a direction substantially opposite to feeding direction of the radiating element for equalizing the antenna directional pattern at receiving band frequencies of the radio apparatus.

3. The antenna according to claim 2, the length of said part of the conductive element being substantially a quarter of the wavelength at an operating frequency of the antenna.

4. The antenna according to claim 1, wherein the conductive element comprises a part pointing from the ground point substantially in feeding direction of the radiating element for changing direction angle of a directional pattern notch at transmitting band frequencies of the radio apparatus.

5. The antenna according to claim 4, said direction angle corresponding to a position of the head of an user of the radio apparatus in a normal use position of the radio apparatus.

6. The antenna according to claim 1, said at least one conductive element being conductive strips belonging to a circuit board internal to the radio apparatus.

7. The antenna according to claim 1, said at least one conductive element being conductive strips on an inner surface of casing of the radio apparatus.

8. The antenna according to claim 1, the radiating element being a helix conductor.

9. The antenna according to claim 1, the radiating element being a planar element and the antenna further comprising a ground plane such that the antenna is a planar inverted F-antenna.

10. A radio apparatus comprising an antenna having a radiating element and a feed conductor thereof connected to the radio apparatus at a feed point, the radio apparatus further comprising, for shaping the directional pattern of the antenna, at least one internal conductive element connected to signal ground in the radio apparatus at a ground point located relatively close to said feed point.