Surface mount type antenna and radio transmitter and receiver using the same

• US 6,657,593 B2
• Filed: 05/28/2002
• Issued: 12/02/2003
• Est. Priority Date: 06/20/2001
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Ishihara, Takashi, Sato, Jin, Nagumo, Shoji, Onaka, Kengo
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Chen, Shih Chao
• Application Number:
  US10/155,118
• Publication Number:
  US 20020196192A1
• Time in Patent Office: 553 Days
• Field of Search: 343/700.MS, 343/702, 343/767, 343/770, 343/846, 343/848, 343/873, 343/893
• US Class Current: 343/700.0MS
• 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 5/357 using a single feed point
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 5/385 Two or more parasitic elements
• CPC Class Codes: H01Q 5/392 the parasitic elements having dual-band or multi-band characteristics
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

A surface mount type antenna includes a loop-shaped fed radiation electrode provided on a substrate, and a non-fed radiation electrode is arranged close to the fed radiation electrode with a gap provided therebetween. One end side of the non-fed radiation electrode is grounded, and the other end side is an open end. A signal is sent to the non-fed radiation electrode from the fed radiation electrode by electromagnetic coupling to perform a resonant operation. The fed radiation electrode and the non-fed radiation electrode generate a double-resonant state. The double resonance extends the frequency band. When the fed radiation electrode and the non-fed radiation electrode are provided on the substrate to define an antenna, the size of the antenna is greatly reduced.

Claims

1. A surface mount type antenna comprising:

a substrate;

at least one fed radiation electrode arranged to receive a signal sent from a signal source and provided on the substrate, wherein said at least one of the fed radiation electrode includes a fed end section side which receives a signal from the signal source and is arranged opposite another end side defining an open end, with a gap provided therebetween; and

at least one non-fed radiation electrode that is provided on the substrate and electromagnetically coupled with said at least one fed radiation electrode to generate a double-resonant state.

2. A surface mount type antenna according to claim 1, wherein the at least one non-fed radiation electrode has a loop shape and includes one ground end connected to ground and an open end arranged opposite to the ground end with a gap provided therebetween.

3. A surface mount type antenna according to claim 1, wherein the at least one fed radiation electrode and the at least one non-fed radiation electrode are arranged to perform a basic-mode resonant operation and a high-order-mode resonant operation having a higher resonant frequency than in the basic mode, and the distance between the open end of the at least one fed radiation electrode or the at least one non-fed radiation electrode and a portion opposite the open end through one of said gaps is changed to adjust the capacitance of a capacitor defined between the open end and the portion opposite to the open end to that corresponding to a specified high-order-mode resonant frequency.

4. A surface mount type antenna according to claim 1, wherein each of the at least one non-fed radiation electrode and the at least one fed radiation electrode has a loop shape, the loop shape of the at least one fed radiation electrode or the at least one non-fed radiation electrode is provided by a slit for a plane-shaped pattern, and the slit is folded once or more times.

5. A surface mount type antenna according to claim 1, wherein the substrate is a dielectric substrate, and the dielectric substrate defines a coupling-amount adjusting element for adjusting the amount of coupling between the at least one fed radiation electrode and the at least one non-fed radiation electrode by the dielectric constant of the substrate.

6. A surface mount type antenna according to claim 1, wherein the at least one fed radiation electrode and the at least one non-fed radiation electrode are arranged to perform a basic-mode resonant operation and a high-order-mode resonant operation having a higher resonant frequency than in the basic mode, the substrate is a dielectric substrate, and the dielectric substrate defines a open-end-capacitor adjusting element for adjusting the capacitance of a capacitor defined between the open end of the at least one loop-shaped fed radiation electrode or the at least one loop-shaped non-fed radiation electrode and a portion opposite the open end by the dielectric constant of the substrate to adjust the high-order-mode resonant frequency.

7. A surface mount type antenna according to claim 1, wherein at least one of a capacity-loaded electrode arranged through a gap adjacent to the at least one fed radiation electrode and having a capacitor defined between itself and the at least one fed radiation electrode and a capacity-loaded electrode arranged through a gap adjacent to the at least one non-fed radiation electrode and having a capacitor defined between itself and the at least one non-fed radiation electrode is provided, and at least one of the capacity-loaded electrodes is electrically connected to the ground.

8. A radio transmitter and receiver comprising surface mount type antenna described in claim 1.

9. A surface mount type antenna comprising:

a substrate;

a signal source;

at least one fed radiation electrode provided on said substrate and arranged to receive a signal sent from the signal source, said at least one of the fed radiation electrode includes a fed end section side which receives a signal from the signal source and an opposite open end with a gap provided therebetween; and

at least one non-fed radiation electrode that is provided on the substrate and electromagnetically coupled with said at least one fed radiation electrode to generate a double-resonant state.

10. A surface mount type antenna according to claim 9, wherein the at least one non-fed radiation electrode has a loop shape and includes a ground end connected to a ground and an open end and an open end arranged opposite the ground end with a gap provided therebetween.

11. A surface mount type antenna according to claim 9, wherein the fed radiation electrode and the non-fed radiation electrode are arranged to perform a basic-mode resonant operation and a high-order-mode resonant operation having a higher resonant frequency than in the basic mode, and the distance between the open end of the loop-shaped fed radiation electrode or the loop-shaped non-fed radiation electrode and a portion opposite the open end through one of said gaps is changed to adjust the capacitance of a capacitor defined between the open end and the portion opposite the open end to that corresponding to a specified high-order-mode resonant frequency.

12. A surface mount type antenna according to claim 9, wherein each of the at least one fed radiation electrode and the at least one non-fed radiation electrode have a loop shape, and the loop shape of the at least one fed radiation electrode or the at least one non-fed radiation electrode is provided by a slit for a plane-shaped pattern, and the slit is folded once or more times.

13. A surface mount type antenna according to claim 9, wherein that the substrate is a dielectric substrate, and the dielectric substrate defines a coupling-amount adjusting element for adjusting the amount of coupling between the at least one fed radiation electrode and the at least one non-fed radiation electrode by the dielectric constant of the substrate.

14. A surface mount type antenna according to claim 9, wherein the at least one fed radiation electrode and the at least one non-fed radiation electrode are arranged to perform a basic-mode resonant operation and a high-order-mode resonant operation having a higher resonant frequency than in the basic mode, the substrate is a dielectric substrate, and the dielectric substrate defines a open-end-capacitor adjusting element for adjusting the capacitance of a capacitor defined between the open end of the at least one loop-shaped fed radiation electrode or the at least one loop-shaped non-fed radiation electrode and a portion opposite the open end by the dielectric constant of the substrate to adjust the high-order-mode resonant frequency.

15. A surface mount type antenna according to claim 9, wherein at least one of a capacity-loaded electrode arranged through a gap adjacent to the at least one fed radiation electrode and having a capacitor defined between itself and the at least one fed radiation electrode and a capacity-loaded electrode arranged through a gap adjacent to the at least one non-fed radiation electrode and having a capacitor defined between itself and the at least one non-fed radiation electrode is provided, and at least one of the capacity-loaded electrodes is electrically connected to the ground.

16. A surface mount type antenna according to claim 9, wherein said at least one fed radiation electrode comprises a plurality of fed radiation electrodes.

17. A surface mount type antenna according to claim 9, wherein said at least one non-fed radiation electrode comprises a plurality of non-fed radiation electrodes.

18. A radio transmitter and receiver comprising a surface mount type antenna described in claim 9.