Antenna element

• US 6,639,559 B2
• Filed: 02/26/2002
• Issued: 10/28/2003
• Est. Priority Date: 03/07/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi, Ltd., Hitachi Metals (Thailand) Ltd.
• Inventors: Kikuchi, Keiko, Aoyama, Hiroyuki, Okabe, Hiroshi, Takeda, Eriko
• Primary Examiner(s): VANNUCCI, JAMES
• Application Number:
  US10/082,092
• Publication Number:
  US 20020126049A1
• Time in Patent Office: 609 Days
• Field of Search: 343/700.MS, 343/702, 343/873, 343/895, 343/846, 343/848, 343/795
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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 9/0414 in a stacked or folded configuration

Abstract

To provide an antenna element having a radiation electrode formed mainly on one surface of a dielectric substrate. The radiation electrode is substantially symmetric in form with respect to the center thereof, and has a first half and a second half with the same direction of main polarization of radiation emitted therefrom. Each of the halves of the radiation electrode may be a quarter-wave antenna for a wavelength of the emitted radiation. A power supply conductor to be connected to a high frequency signal source is connected to the first half of the radiation electrode, and a ground conductor to be connected to a ground is connected to the second half. A total impedance of the first half of the radiation electrode and the power supply conductor and a total impedance of the second half of the radiation electrode and the ground conductor can substantially match to one another, so that resonance between the halves of the radiation electrode can be enhanced and a wider bandwidth can be realized.

Claims

1. An antenna element comprising:

a dielectric substrate,

a radiation electrode of an electric conductor formed mainly on a surface of the dielectric substrate,

the radiation electrode having a first and a second halves,

the first and the second halves being substantially symmetric in form to one another with respect to a center of the radiation electrode, and radiating with the same direction of main polarization of radiation emitted from the radiation electrode,

the first half having a first open end at its outer end, another end at a distance of a quarter radiation wavelength along the radiation electrode from the first open end, and a first connection terminal between the first open end and the other end of the first half,

the second half having a second open end at its outer end and a second connection terminal at a distance of a quarter radiation wavelength along the radiation electrode from the second open end, the second connection terminal being at a distance from the first connection terminal on the radiation electrode,

a power supply conductor formed on the dielectric substrate and connected to the first connection terminal at one end of the power supply conductor and having at the other end of the power supply conductor a terminal for connecting to a high frequency signal source, and a ground conductor formed on the dielectric substrate and connected to the second connection terminal at one end of the ground conductor and having at the other end of the ground conductor a terminal for connecting to a ground,

wherein a total conductor length of a portion of the first half between the first open end and the first connection terminal, and the power supply conductor is so different from a total conductor length of a portion of the second half, between the second open end and the second connection terminal, and the ground conductor that

the total impedance of the power supply conductor and the portion of the first half between the first open end of the first half and the terminal of the power supply conductor at the other end for connecting to a high frequency signal source and the internal impedance of the high frequency signal source substantially match, in total impedance, the ground conductor and the portion of the second half between the second open end of the second half and the terminal of the ground conductor at the other end for connecting to a ground.

2. An antenna element as set forth in claim 1, wherein the first and the second halves of the radiation electrode connect capacitively to a ground at the first and at the second open ends, respectively.

3. An antenna element as set forth in claim 2, further comprising ground electrodes, formed adjacent to the first and the second open ends on the dielectric substrate, for connecting a ground, each of the ground electrodes connecting capacitively to the first and the second halves of the radiation electrode at the first and at the second open ends, respectively.

4. An antenna element as set forth in claim 3, wherein the radiation electrode is in a meandering form.

5. An antenna element as set forth in claim 1, wherein the electric conductor forming the radiation electrode discontinues between the other end of the first half and the second connection terminal and is divided into the first and the second halves, and the first connection terminal is positioned at the other end of the first half.

6. An antenna element as set forth in claim 5, wherein the radiation electrode is in a meandering form.

7. An antenna element as set forth in claim 5, wherein the electric conductor width of each of the first and the second halves of the radiation electrode is narrowing from the center toward each of the open ends and the distance between the electric conductors of each of the first and the second halves is increasing from the center toward each of the open ends.

8. An antenna element as set forth in claim 5, wherein the ground conductor has an impedance adjustment conductor on a surface of the dielectric substrate.

9. An antenna element as set forth in claim 1, wherein the electric conductor forming the radiation electrode continues at the other end of the first half from the first half to the second half and has the second connection terminal at the other end of the first half.

10. An antenna element as set forth in claim 9, wherein the radiation electrode is in a meandering form.

11. An antenna element as set forth in claim 9, wherein the electric conductor width of each of the first and the second halves of the radiation electrode is narrowing from the center toward each of the open ends and the distance between the electric conductors of each of the first and the second halves is increasing from the center toward each of the open ends.

12. An antenna element as set forth in claim 9, wherein the ground conductor has an impedance adjustment conductor on a surface of the dielectric substrate.

13. An antenna element as set forth in claim 1, further comprising another dielectric substrate formed on the surface of the dielectric substrate on which the radiation electrode is formed.

14. The antenna element as set forth in claim 1, wherein said portion of the first half has a length less than that of said portion of the second half.

15. A telecommunication device comprising:

a printed wiring board having a ground area of the board with a ground conductor, a ground-free area of the board without a ground conductor and a high frequency signal lead, and

an antenna element,

the antenna element comprising;

a dielectric substrate,

a radiation electrode of an electric conductor formed mainly on a surface of the dielectric substrate,

the radiation electrode having a first and a second halves,

the first and the second halves being substantially symmetric in form to one another with respect to a center of the radiation electrode, and radiating with the same direction of main polarization of radiation emitted from the radiation electrode,

the first half having a first open end at its outer end, another end at a distance of a quarter radiation wavelength along the radiation electrode from the first open end, and a first connection terminal between the first open end and the other end of the first half,

the second half having a second open end at its outer end and a second connection terminal at a distance of a quarter radiation wavelength along the radiation electrode from the second open end, the second connection terminal being at a distance from the first connection terminal on the radiation electrode,

a power supply conductor formed on the dielectric substrate and connected to the first connection terminal at one end of the power supply conductor and having at the other end of the power supply conductor a terminal connected to the high frequency signal lead on the printed wiring board, and

a ground conductor formed on the dielectric substrate and connected to the second connection terminal at one end of the ground conductor and having at the other end of the ground conductor a terminal connected to a ground on the printed wiring board,

wherein a total conductor length of a portion of the first half, between the first open end and the first connection terminal, and the power supply conductor is so different from a total conductor length of a portion of the second half between the second open end and the second connection terminal and the ground conductor that

the total impedance of the power supply conductor and the portion of the first half between the first open end of the first half and the terminal, at the other end of the power supply conductor, connected to the high frequency signal lead and the impedance of the high frequency signal source substantially match, in total impedance, the ground conductor and the portion of the second half between the second open end of the second half and the terminal, at the other end of the ground conductor, connected to the ground on the printed wiring board,

wherein the antenna element is mounted on the ground-free area of the board so that a dielectric substrate surface other than the dielectric substrate surface on which the radiation electrode is formed faces the ground-free area.

16. A telecommunication device as set forth in claim 15, wherein the printed wiring board has the ground-free area of the board between the ground area of the board and a side edge of the board and

the antenna element is mounted on the ground-free area of the board so that the dielectric substrate surface having the radiation electrode is adjacent to the side edge of the board and a dielectric substrate surface other than the dielectric substrate surface having the radiation electrode faces the ground-free area of the board.

17. A telecommunication device as set forth in claim 16, wherein the antenna element further comprises ground electrodes, formed adjacent to the first and the second open ends on the dielectric substrate, connected to the ground conductor on the printed wiring board, each of the ground electrodes connecting capacitively to the first and the second halves at the first and the second open ends, respectively.

18. A telecommunication device as set forth in claim 17, wherein the radiation electrode is in a meandering form.

19. A telecommunication device as set forth in claim 15, wherein the electric conductor forming the radiation electrode discontinues between the other end of the first half and the second connection terminal and is divided into the first and the second halves, and the first connection terminal is positioned at the other end of the first half.

20. A telecommunication device as set forth in claim 19, wherein the electric conductor width of each of the first and the second halves of the radiation electrode is narrowing from the center toward each of the open ends and the distance between the electric conductors of each of the first and the second halves is increasing from the center toward each of the open ends.

21. A telecommunication device as set forth in claim 19, wherein the ground conductor has an impedance adjustment conductor on a surface of the dielectric substrate.

22. A telecommunication device as set forth in claim 15, wherein the electric conductor forming the radiation electrode continues at the other end of the first half from the first half to the second half and has the second connection terminal at the other end of the first half.

23. A telecommunication device as set forth in claim 22, wherein the electric conductor width of each of the first and the second halves of the radiation electrode is narrowing from the center toward each of the open ends and the distance between the electric conductors of each of the first and the second halves is increasing from the center toward each of the open ends.

24. A telecommunication device as set forth in claim 22, wherein the ground conductor has an impedance adjustment conductor on a surface of the dielectric substrate.

25. The antenna element as set forth in claim 15, wherein said portion of the first half has a length less than that of said portion of the second half.