Antenna Device and Portable Radio Communication Device Comprising Such Antenna Device

• US 20080287084A1
• Filed: 07/09/2004
• Published: 11/20/2008
• Est. Priority Date: 07/11/2003
• Status: Abandoned Application

• Current Assignee: Laird Technologies AB (Laird PLC)
• Original Assignee: AMC Centurion AB (DuPont de Nemours, Inc.)
• Inventors: von Arbin, Axel, Olsson, Magnus, Starck, Jonas, Katsunori, Ishimiya, Krebs, Christer
• Application Number:
  US10/563,458
• Publication Number:
  US 20080287084A1
• Time in Patent Office: Days
• US Class Current: 455/271
• CPC Class Codes: H01Q 1/243 with built-in antennas
• 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 7/005 with variable reactance for tuning the antenna
• CPC Class Codes: H01Q 9/14 Length of element or elements adjustable telescopic elements H01Q1/10
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H

Abstract

An antenna device for a portable radio communication device adapted for receiving radio signals comprises an internal radiating element (10) comprising at least one feeding portion (21, 22) connected to a receiver circuit (40). The radiating element (10) comprises an electrical impedance (30) that is controllable in dependence on the desired frequency range of the received signals, wherein the feeding portion (21, 22) is connected to a feeding input (40a, 40b) on the receiver circuit and the control input of the controllable electrical impedance (30) is connected to an output (40c) on the receiver circuit (40) intended for the control of the VCO resonance frequency of the receiver circuit. In that way an antenna device can be provided inside the casing of a small sized portable radio communication device, which has good performance throughout a narrow sub-band of a frequency band having a relatively low frequency, wherein the narrow sub-band can be adjusted in frequency so as to cover the entire frequency band, such as the FM radio band.

Claims

1. An antenna device for a portable radio communication device adapted for receiving radio signals, said antenna device comprising

an internal radiating element (10) comprising at least one feeding portion (21, 22) connected to a receiver circuit (40),

characterised in that

the radiating element (10) comprises an electrical impedance (30;

30′

;

30″

) that is controllable in dependence on the desired frequency range of the received signals,

wherein the at least one feeding portion (21, 22) is connected to a feeding input (40a, 40b) on the receiver circuit, and

wherein the control input of the controllable electrical impedance (30) is connected to an output (40c) on the receiver circuit (40) intended for the control of the VCO resonance frequency of the receiver circuit.

2. The antenna device according to claim 1, wherein the impedance (30;

30′

;

30″

) is a capacitive impedance.

3. The antenna device according to claim 2, wherein the electrical impedance is a varactor diode (30).

4. The antenna device according to claim 1, wherein the impedance (30) is an inductive impedance.

5. The antenna device according to any of claims 1-4, wherein the radio signals for which the antenna 5 device is adapted have a frequency below 110 MHz, preferably between 76 and 110 MHz, and even more preferably between 88 and 108 MHz.

6. The antenna device according to any of claims 1-5, wherein the radiating element is a loop (10).

7. The antenna device according to any of claims 1-6, wherein the radiating element (10′

) is arranged in several turns.

8. The antenna device according to any of claims 1-7, wherein the radiating element (10) is arranged on a battery package (230).

9. The antenna device according to claim 8, wherein the radiating element (10) is connected to the receiver circuit (40) by means of connectors provided on the battery package (230).

10. The antenna device according to any of claims 1-9, wherein the radiating element (10″

) is arranged as a spiral.

11. The antenna device according to any of claims 1-9, wherein the radiating element (10′

) of the antenna device is provided outside of the edge of a PCB (210) provided in the radio communication device.

12. The antenna device according to any of claims 1-11, wherein the radiating element (10) is provided above a dielectric material.

13. The antenna device according to any of claims 1-12, comprising at least two orthogonal radiating elements (10), each comprising at least one feeding portion (21, 22) connected to the receiver circuit and an electrical impedance.

14. A portable radio communication device comprising an antenna device according to any of the preceding claims.