Mobile phone, analysis device included therein, and analysis method

• US 20030228891A1
• Filed: 06/05/2003
• Published: 12/11/2003
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Hankui, Eiji, Kobayashi, Naoki
• Granted Patent: US 7,162,284 B2
• Time in Patent Office: Days
• US Class Current: 455/575.5
• 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 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04B 7/06 at the transmitting station
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A mobile phone has an upper antenna at the top of a casing constituting a body and a lower antenna at the bottom of the casing. The mobile phone includes an influence-on-antenna evaluation unit for evaluating the influence of the ambient environment on each of the antennas by determining an input impedance (Z) of each antenna at predetermined time intervals during connection and by comparing the determined input impedance with a predetermined input-impedance reference value (Z0). Transmission power corresponding to the amount of radio waves radiated is supplied to the antenna that is less affected by the ambient environment and transmission power is not supplied to the antenna that is more affected by the ambient environment.

Claims

1. A mobile phone comprising:

a casing that constitutes a body;

an upper antenna at the top of the casing;

a lower antenna at the bottom of the casing; and

an influence-on-antenna evaluation unit for evaluating the influence of the ambient environment on each of the antennas by determining an input impedance (Z) of each antenna at predetermined time intervals during connection and by comparing the determined input impedance with a predetermined input-impedance reference value (Z0), and wherein

transmission power corresponding to the amount of radio waves radiated is supplied to the antenna that is less affected by the ambient environment and transmission power is not supplied to the antenna that is more affected by the ambient environment.

2. A mobile phone according to claim 1, wherein:

the influence of the ambient environment on each of the antennas is expressed as a variation in the input impedance (Z) of the antenna with reference to the input-impedance reference value (Z0) and the variation is used as an index of the influence.

3. A mobile phone according to claim 1, wherein:

the variation is given by adding the square differences (|Z(ω

_i)-Z0(ω

_i)|²) between input impedances (Z(ω

_i)) and input-impedance reference values (Z0(ω

_i)) at a plurality of frequency points ω

_i (i=1, 2, . . . N (an integer)) within a predetermined frequency band.

4. A mobile phone according to claim 1, wherein:

the input-impedance reference value (Z0) is the impedance of an antenna located in free space.

5. A mobile phone according to claim 1, wherein:

at least one said upper antenna and at least one said lower antenna are attached to any points on the casing.

6. A mobile phone according to claim 1, wherein:

the upper antenna and the lower antenna are linear antennas, planar antennas, or the combination of the linear antennas and the planar antennas.

7. A mobile phone according to claim 1, wherein:

the upper antenna and the lower antenna are inverted L antennas.

8. A mobile phone according to claim 1, wherein:

the upper antenna and the lower antenna are helical antennas.

9. A mobile phone according to claim 1, wherein:

the upper antenna and the lower antenna are monopole antennas.

10. A mobile phone according to claim 1, wherein:

the mobile phone being a foldable mobile phone, a first casing and a second casing constituting the casing of the foldable mobile phone,

the first casing and the second casing being connected by a hinge part which allows the first and second casings to close.

11. A mobile phone according to claim 10, wherein:

the upper antenna and the lower antenna constitute a new equivalent antenna when the first and the second casings of the foldable mobile phone are closed.

12. A mobile phone according to claim 10, wherein:

the upper antenna and the lower antenna of the foldable mobile phone are L antennas,

the upper antenna being attached to the center of the top edge of the first casing in the upper half of the foldable mobile phone,

the lower antenna being attached to the center of the bottom edge of the second casing in the lower half of the foldable mobile phone,

the upper antenna being attached to the first casing in a direction opposite to the lower antenna when the two casings are not closed,

the upper antenna and the lower antenna being aligned with each other when the two casings are closed and the upper antenna and the lower antenna behave like a dipole antenna.

13. An analysis device included in the mobile phone according to claim 4, the device comprising:

a free-space-impedance storage unit for storing in advance the input-impedance reference value (Z0) of an antenna in free space;

an upper-impedance calculation unit for calculating the input impedance of the upper antenna during connection;

a lower-impedance calculation unit for calculating the input impedance of the lower antenna during connection;

an upper-impedance-variation calculation unit for calculating the square difference between the input impedance of the upper antenna and the input-impedance reference value in free space;

a lower-impedance-variation calculation unit for calculating the square difference between the input impedance of the lower antenna and the input-impedance reference value in free space;

a comparison unit for comparing an upper-impedance variation calculated by the upper-impedance-variation calculation unit with a lower-impedance variation calculated by the lower-impedance-variation calculation unit; and

a switch unit for switching on or off the upper antenna and the lower antenna, and wherein;

the switch unit supplies power only to the lower antenna by transferring no power from a power amplifying unit to a feed unit in the upper antenna when the upper-impedance variation is greater than the lower-impedance variation based on the comparison result given by the comparison unit, and wherein;

the switch unit supplies power only to the upper antenna by transferring no power from the power amplifying unit to the lower antenna when the lower-impedance variation is greater than the upper-impedance variation.

14. An analysis device according to claim 13, wherein:

the upper antenna and the lower antenna are inverted L antennas.

15. An analysis device according to claim 13, wherein:

the upper antenna and the lower antenna are helical antennas.

16. An analysis device according to claim 13, wherein:

the upper antenna and the lower antenna are monopole antennas.

17. An analysis method of the mobile phone according to claim 4, the method comprising:

a free-space-impedance storage step for storing the input-impedance reference value (Z0) of an antenna in free space;

an upper-impedance calculation step for calculating the input impedance of the upper antenna during connection;

a lower-impedance calculation step for calculating the input impedance of the lower antenna during connection;

an upper-impedance-variation calculation step for calculating the square difference between the input impedance of the upper antenna and the input-impedance reference value in free space;

a lower-impedance-variation calculation step for calculating the square difference between the input impedance of the lower antenna and the input-impedance reference value in free space;

a comparison step for comparing an upper-impedance variation calculated by the upper-impedance-variation calculation step with a lower-impedance variation calculated by the lower-impedance-variation calculation step; and

a switching step for switching on or off the upper antenna and the lower antenna, and wherein

in the switching step, power is supplied only to the lower antenna by transferring no power from a power amplifying unit to a feed unit in the upper antenna when the upper-impedance variation is greater than the lower-impedance variation based on the comparison result given by the comparison step, and wherein

in the switching step, power is supplied only to the upper antenna by transferring no power from the power amplifying unit to the lower antenna when the lower-impedance variation is greater than the upper-impedance variation.

18. An analysis method of the mobile phone, according to claim 17, wherein:

the upper antenna and the lower antenna are inverted L antennas.

19. An analysis method of the mobile phone, according to claim 17, wherein:

the upper antenna and the lower antenna are helical antennas.

20. An analysis method of the mobile phone, according to claim 17, wherein:

the upper antenna and the lower antenna are monopole antennas.