Antenna for portable radio communication device and method of transmitting radio signal

• US 6,597,320 B2
• Filed: 09/06/2001
• Issued: 07/22/2003
• Est. Priority Date: 09/11/2000
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Original Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Inventors: Inoue, Goro, Ohoka, Shinji, Maeda, Noboru
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US09/946,562
• Publication Number:
  US 20020030630A1
• Time in Patent Office: 684 Days
• Field of Search: H01/Q.112, H01/Q.124, 343/718, 343/702, 343/767, 343/866, 343/741
• US Class Current: 343/718
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 1/44 using equipment having another main function to serve additionally as an antenna , e.g. means for giving an antenna an aesthetic aspectH01Q1/27 - H01Q1/34 take precedence

Abstract

An antenna for a portable radio communication device is constructed with a conductive shield plate provided in a casing made of resin and shaped to be worn on a human body. The shield plate is capacitively coupled with a part of the human body to operate as an antenna element. A conductive cover of a battery is disposed in the casing to operate as the other antenna element. The antenna elements thus form an electric field-type dipole antenna. The conductive cover of the battery may also be capacitively coupled with the other part of the human body, so that the antenna operate as a loop antenna which uses the human body. The electric field-type antenna may be combined with a magnetic field-type antenna to make the directivity of the antenna to be isotropic.

Claims

1. An antenna for a portable radio communication device having a casing comprising:

a first electrode member disposed in the casing as a first antenna element; and

a second electrode member provided as a second antenna element to form an electric field-type dipole antenna in pair with the first electrode member,

wherein the first electrode member is constructed to be capacitively coupled with a human body thorough the casing so that the human body is used as a part of the first antenna element.

2. The antenna as in claim 1, wherein one of the electrode members is a conductive cover of a battery of the radio communication device.

3. The antenna as in claim 1, wherein the casing is made of an insulating material having a predetermined permittivity.

4. An antenna for a portable radio communication device having a circuit plate of multiple layers in a casing comprising:

a conductive pattern formed on top surfaces and side surfaces of a plurality of the multiple layers to provide one of a loop antenna and a slot antenna three-dimensionally;

a first electrode member disposed in the casing as a first antenna element; and

a second electrode member provided as a second antenna element to form an electric field-type dipole antenna in pair with the first electrode member,

wherein the first electrode member is constructed to be capacitively coupled with a human body through the casing so that the human body is used as a part of the first antenna element, and

wherein the dipole antenna and the one of the loop antenna and the slot antenna are combined to make an antenna directivity more isotropic than any of the dipole antenna, the loop antenna and the slot antenna.

5. An antenna for a portable radio communication device having a casing comprising:

a first electrode member disposed in the casing; and

a second electrode member disposed in the casing,

wherein the first electrode member and the second electrode member are constructed to be capacitively coupled with different parts of a human body thorough the casing, respectively, to provide a loop antenna via a part of the human body.

6. The antenna as in claim 5, further comprising:

a conductive pattern formed on top surfaces and side surfaces of a plurality of multiple layers of a circuit plate to provide one of a loop antenna and a slot antenna three-dimensionally.

7. A method of transmitting a radio signal from a portable radio communication device having a casing made of a resin material, a transmitter circuit disposed in the casing and a conductive member disposed in the casing, the transmitter circuit being connected to the conductive member, the method comprising the steps of:

attaching the casing to a part of a human body in direct contact therewith so that the conductive member is capacitively coupled with the part of human body through the casing to form an electric field-type antenna; and

applying an output signal of the transmitter circuit to the conductive member so that the output signal is transmitted from the electric field-type antenna partly formed by the human body.

8. The method as in claim 7, wherein the conductive member is one of a conductive plate and a conductive cover of a battery which supplies electric power to the transmitter circuit.

9. The method as in claim 7, wherein another conductive member is provided in the casing and connected to the transmitter circuit so that the conductive members are used as two antenna elements of a dipole antenna.

10. A portable radio communication device comprising:

a circuit plate of multiple layers that have respective through holes;

a transmitter provided on the circuit plate; and

conductive patterns formed on top surfaces of the multiple layers and connected to each other via the through holes of the multiple layers, thereby forming a magnetic field-type antenna connected to the transmitter.

11. The portable radio communication device as in claim 10, further comprising:

a battery; and

a shield plate layered with the circuit plate to form an electric field-type antenna with the battery and a part of a human body.

12. The portable radio communication device as in claim 11, further comprising:

a resin casing having a part which is shaped to be sandwiched between the shield plate and a finger of the human body.