Antenna for portable terminal and portable terminal using same

• US 7,995,001 B2
• Filed: 02/17/2004
• Issued: 08/09/2011
• Est. Priority Date: 02/18/2003
• Status: Expired due to Fees

• Current Assignee: Tadahiro Ohmi
• Original Assignee: Tadahiro Ohmi
• Inventors: Nakamura, Fumiaki, Ohmi, Tadahiro, Morimoto, Akihiro
• Primary Examiner(s): Choi; Jacob Y
• Assistant Examiner(s): Karacsony; Robert
• Application Number:
  US10/546,191
• Publication Number:
  US 20060119518A1
• Time in Patent Office: 2,730 Days
• Field of Search: 343/700.MS, 343/911.R, 343/787
• US Class Current: 343/911.00R
• CPC Class Codes: H01Q 9/0485 Dielectric resonator antennas

Abstract

A dielectric resonator antenna which emits an electric wave by having a dielectric body resonate is disclosed. A magnetic material is contained in the electric body, thereby increasing the relative permeability to more than 1 and lowering the relative permittivity. Consequently, the Q-value of the resonance can be lowered while maintaining the rate of wavelength shortening. With this technique, a broadband dielectric resonator antenna can be realized.

Claims

1. A dielectric resonator antenna being adapted to emit a radio wave by resonating a signal, said dielectric resonator antenna comprising:

a conductive plate having a first and a second surface which are faced opposite to each other;

a dielectric placed opposite to said first surface of the conductive plate, said dielectric having a relative permeability (μ

ra) of μ

ra >

1;

an electrode provided to said dielectric and adapted to be supplied with said signal; and

a magneto-dielectric layer placed on said second surface of the conductive plate;

wherein said dielectric contains a magnetic material and a dielectric material to have frequency vs. antenna input impedance characteristics in which frequencies are partly superimposed in a half of resonance peak between a first mode on a low frequency side and a second mode on a high frequency side, and

wherein said magneto-dielectric layer has a relative permeability (μ

rr) and a relative permittivity (∈

rr), where μ

rr is not less than ∈

rr, whereby said magneto-dielectric layer produces a mirror-image effect with respect to an electric field.

2. The dielectric resonator antenna according to claim 1, wherein said dielectric is mounted directly on said first surface of the conductive plate.

3. The dielectric resonator antenna according to claim 1, further comprising an insulator which is mounted on said first surface of the conductive plate and has a relatively permittivity (∈

rd) of ∈

rd>

1, wherein said dielectric is mounted on said insulator.

4. The dielectric resonator antenna according to claim 1, wherein a wavelength shortening coefficient is 200 or less.

5. The dielectric resonator antenna according to claim 1, wherein a wavelength shortening coefficient is 100 or less.

6. The dielectric resonator antenna according to claim 1, wherein a wavelength shortening coefficient is 50 to 3.

7. The dielectric resonator antenna according to claim 1, wherein said magnetic material contains at least one of a simple substance of cobalt, manganese, or iron, and an alloy and a compound magnetic material each containing at least one of cobalt, manganese, and iron.

8. The dielectric resonator antenna according to claim 1, wherein said dielectric material contains one or both of a resin material containing at least one of liquid crystal resin, epoxy resin, olefin-based resin, fluororesin, BT (bismaleimide triazine) resin, and polyimide resin and an inorganic dielectric material containing at least one of silica (SiO₂, SiO), silicon nitride (SiN, Si₃N₄), zirconia (ZrO, ZrO₂), hafnia (HfO, HfO₂), titania (TiO, TiO₂), aluminum nitride (AIN), SrBi₂Ta₂O₉, SrBi₂(Ta_1-x,Nb_x)₂O₉, Sr₂(Ta_1-x,Nb_x)₂O ₇, BST (barium strontium titanate), PZT (lead zirconate titanate), alumina (Al₂O₃), BiTiO₃, SrTiO₃, PbZrO₃, PbTiO₃, and CaTiO₃.

9. The dielectric resonator antenna according to claim 8, wherein fine powder of said magnetic material is dispersed into said resin material.

10. The dielectric resonator antenna according to claim 9, wherein said inorganic dielectric material is further dispersed into said resin material.

11. A portable terminal including the dielectric resonator antenna according to claim 1.

12. A portable terminal including a plurality of dielectric resonator antennas each according to claim 1 and being capable of adjusting a radio wave radiation direction.

13. A method of manufacturing a dielectric resonator antenna that emits a radio wave by radiating a radio wave to a resonator formed by a dielectric and resonating said radiated radio wave in said dielectric, said method comprising:

adjusting a relative permittivity on condition that a relative permeability exceeds 1, to thereby obtain a magneto-dielectric material that can achieve a predetermined wavelength shortening coefficient;

forming said dielectric by the use of said magneto-dielectric material, wherein said dielectric contains a magnetic material and a dielectric material to have frequency vs. antenna input impedance characteristics in which frequencies are partly superimposed in a half of resonance peak between a first mode on a low frequency side and a second mode on a high frequency side; and

forming a magneto-dielectric layer having a relative permeability (μ

rr) and a relative permittivity (∈

rr), where μ

rr is not less than ∈

rr, whereby said magneto-dielectric layer produces a mirror-image effect with respect to an electric field,

wherein said magneto-dielectric material is produced by mixing together the magnetic material and the dielectric material.

14. A method of manufacturing a dielectric resonator antenna that emits a radio wave by radiating a radio wave to a resonator formed by a dielectric and resonating said radiated radio wave in said dielectric, said method comprising:

adjusting a relative permittivity on condition that a relative permeability exceeds 1, to thereby obtain a magneto-dielectric material that can achieve a predetermined wavelength shortening coefficient;

forming said dielectric by the use of said magneto-dielectric material, wherein said dielectric contains a magnetic material and a dielectric material to have frequency vs. antenna input impedance characteristics in which frequencies are partly superimposed in a half of resonance peak between a first mode on a low frequency side and a second mode on a high frequency side; and

forming a magneto-dielectric layer having a relative permeability (μ

rr) and a relative permittivity (∈

rr), where μ

rr is not less than ∈

rr, whereby said magneto-dielectric layer produces a mirror-image effect with respect to an electric field.

15. The method according to claim 14, wherein said magnetic material contains at least one of a simple substance of cobalt, manganese, or iron, and an alloy and a compound magnetic material each containing at least one of cobalt, manganese, and iron.

16. The method according to claim 14, wherein said dielectric material contains one or both of a resin material containing at least one of liquid crystal resin, epoxy resin, olefin-based resin, fluororesin, BT (bismaleimide triazine) resin, and polyimide resin and an inorganic dielectric material containing at least one of silica (SiO₂, SiO), silicon nitride (SiN, Si₃N₄), zirconia (ZrO, ZrO₂), hafnia (HfO, HfO₂), titania (TiO, TiO₂), aluminum nitride (AIN), SrBi₂Ta₂O₉, SrBi₂(Ta₁₋

x,Nb_x)₂O₉, Sr₂(Ta <sub>1−

x</sub>,Nb_x)₂O₇, BST (barium strontium titanate), PZT (lead zirconate titanate), alumina (Al₂O₃), BiTiO₃, SrTiO₃, PbZrO₃, PbTiO₃, and CaTiO₃.

17. The method according to claim 16, further comprising dispersing fine powder of said magnetic material into said resin material.

18. The method according to claim 17, further comprising dispersing said inorganic dielectric material into said resin material.