ANTENNA DEVICE AND WIRELESS COMMUNICATION TERMINAL

• US 20110134014A1
• Filed: 05/26/2010
• Published: 06/09/2011
• Est. Priority Date: 07/27/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kuramoto, Mikio, Kondo, Toshinori, Takebe, Hiroyuki
• Granted Patent: US 8,743,014 B2
• Time in Patent Office: Days
• US Class Current: 343/876
• 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 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• 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

At least three resonance frequencies are obtained by two antenna elements. The antenna device includes antenna elements (11) and (12), a wireless section (20) for supplying power to each of the antenna elements (11) and (12), a PIN diode (16) for electrically connecting and disconnecting the antenna element (11) and the wireless section (20) with/from each other, the antenna elements (11) and (12) being provided so as to be capacitively coupled to each other during the electrical disconnection between the antenna element (11) and the wireless section (20) which electrical disconnection is made by the PIN diode (16).

Claims

1. An antenna device comprising:

a first antenna element;

a second antenna element;

a power supply section for supplying power to each of the first antenna element and the second antenna element; and

a switching element for electrically connecting and disconnecting the first antenna element and the power supply section with/from each other,

the first antenna element and the second antenna element being provided so as to be capacitively coupled to each other during the electrical disconnection between the first antenna element and the power supply section which electrical disconnection is made by the switching element.

2. The antenna device as set forth in claim 1, further comprising:

a first power supply path through which the first antenna element and the power supply section are electrically connected; and

a second power supply path through which the second antenna element and the power supply section are electrically connected,

the switching element being provided in the first power supply path,

the first antenna element and the first power supply path are connected with each other at a first connecting part,

the second antenna element and the second power supply path are connected with each other at a second connecting part,

a distance between the first connecting part and the second connecting part being more than 0 (zero) and not more than λ

/15 which is one-fifteenth of a wavelength λ

where an electrical length of the first antenna element is λ

/4.

3. The antenna device as set forth in claim 1, wherein the switching element is a semiconductor element which becomes conductive or non-conductive according to whether or not a forward voltage of a specified value is applied to the switching element.

4. The antenna device as set forth in claim 3, wherein the switching element makes the electrical disconnection between the first antenna element and the power supply section in response to application of a reverse voltage to the switching element.

5. The antenna device as set forth in claim 3, further comprising direct current supply means for supplying a direct current to the switching element during the electrical connection between the first antenna element and the power supply section, the direct current being in proportion to a level of transmission power under which a transmitted wave is radiated from each of the first antenna element and the second antenna element.

6. The antenna device as set forth in claim 1, further comprising an impedance matching circuit for changing a impedance matching value in accordance with whether the first antenna element and the power supply section are electrically connected or disconnected with/from each other by the switching element.

7. The antenna device as set forth in claim 2, wherein a ratio between (i) a resonance frequency f which is in association with the wavelength λ

and (ii) a frequency f′

at which the second antenna element resonates is substantially 1;

2.

8. The antenna device as set forth in claim 1, wherein:

the first antenna element and the second antenna element are at right angles to each other; and

the first antenna element and the second antenna element have an identical electrical length during the electrical connection between the first antenna element and the power supply section.

9. The antenna device as set forth in claim 1, wherein frequencies at which the first antenna element and/or the second antenna element resonate are in conformity with different frequency bands for use in wireless communication systems, depending on whether the first antenna element and the power supply section are electrically connected or disconnected with/from each other.

10. A wireless communication terminal comprising an antenna device recited claim 1.