System and method for impedance matching an antenna to sub-bands in a communication band

• US 20050007291A1
• Filed: 07/26/2004
• Published: 01/13/2005
• Est. Priority Date: 02/12/2002
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Fabrega-Sanchez, Jorge, Poilasne, Gregory, Toncich, Stanley S., Tran, Allen
• Granted Patent: US 7,176,845 B2
• Time in Patent Office: Days
• US Class Current: 343/860
• CPC Class Codes: G01R 27/2694 Measuring dielectric loss, e.g. loss angle, loss factor or power factor
• CPC Class Codes: H01G 7/06 having a dielectric selected for the variation of its permittivity with applied voltage, i.e. ferroelectric capacitors electrets H01G7/02
• CPC Class Codes: H01L 27/0808 Varactor diodes
• CPC Class Codes: H01P 1/203 Strip line filters
• CPC Class Codes: H01P 1/20336 Comb or interdigital filters
• CPC Class Codes: H01P 1/20363 Linear resonators
• CPC Class Codes: H01P 1/20381 Special shape resonators
• CPC Class Codes: H01P 1/2039 Galvanic coupling between Input/Output
• CPC Class Codes: H01P 1/2056 Comb filters or interdigital filters with metallised resonator holes in a dielectric block
• CPC Class Codes: H01P 1/213 combining or separating two or more different frequencies H01P1/215 takes precedence
• CPC Class Codes: H01P 5/04 with variable factor of coupling
• CPC Class Codes: H01Q 1/00 Details of, or arrangements associated with, antennas arrangements for varying orientation of directional pattern H01Q3/00
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 13/06 Waveguide mouths horns H01Q13/02
• CPC Class Codes: H01Q 13/203 Leaky coaxial lines
• CPC Class Codes: H01Q 13/22 Longitudinal slot in boundary wall of waveguide or transmission line H01Q13/203 takes precedence
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0442 : with particular tuning means
• CPC Class Codes: H01Q 9/16 : with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/28 : Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H01Q 9/30 : with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/42 : with folded element, the folded parts being spaced apart a small fraction of the operating wavelength
• CPC Class Codes: H03B 5/04 : Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/1841 : the frequency-determining element being a strip line resonator H03B5/1805, H03B5/1817, H03B5/1864 and H03B5/1882 take precedence
• CPC Class Codes: H03B 5/362 : the amplifier being a single transistor H03B5/364 - H03B5/368 take precedence
• CPC Class Codes: H03F 1/56 : Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/294 : the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 : Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 3/191 : Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03H 7/38 : Impedance-matching networks
• CPC Class Codes: H03J 5/246 : using electronic means H03J5/244 takes precedence
• CPC Class Codes: H03L 1/022 : by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature H03L1/021 takes precedence
• CPC Class Codes: H03L 7/18 : using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence
• CPC Class Codes: H04B 1/0053 : with common antenna for more than one band
• CPC Class Codes: H04B 1/0458 : Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H
• CPC Class Codes: H04B 1/30 : for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A sub-band antenna matching method and an antenna matching system for selectively matching a communication bandwidth segment impedance have been provided. The method comprises: accepting a frequency-dependent impedance from an antenna; and, selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band. In some aspects, the method selectively supplies a conjugate impedance match for the antenna at a sub-band of a second communication band. More specifically, the method comprises: tuning a first tuning circuit to a first frequency; simultaneously tuning a second tuning circuit to a second frequency to match the antenna at a low end of the first communication band. Likewise, the first tuning circuit is tuned to a third frequency and the second tuning circuit is tuned to a fourth frequency to match the antenna at a high end of the first communication band in response to the third and fourth frequencies.

Claims

1. An antenna matching system for selectively matching a communication bandwidth segment impedance, the system comprising:

an antenna having an interface port with a frequency-dependent impedance;

a sub-band matching circuit including an output port connected to the antenna interface port, selectively supplying a conjugate impedance at a sub-band of a first communication band.

2. The system of claim 1 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the first communication band and at a high end of the first communication band.

3. The system of claim 2 wherein the sub-band matching circuit supplies a conjugate impedance at a sub-band of a second communication band.

4. The system of claim 3 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the second communication band and at a high end of the second communication band.

5. The system of claim 4 wherein the sub-band matching circuit includes:

a first tuning circuit; and

,

a second tuning circuit.

6. The system of claim 5 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the first communication band in response to tuning the first tuning circuit to a first frequency and tuning the second tuning circuit to a second frequency.

7. The system of claim 6 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a high end of the first communication band in response to tuning the first tuning circuit to a third frequency and tuning the second tuning circuit to a fourth frequency.

8. The system of claim 7 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the second communication band in response to tuning the first tuning circuit to a fifth frequency and tuning the second tuning circuit to a sixth frequency.

9. The system of claim 8 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a high end of the second communication band in response to tuning the first tuning circuit to a seventh frequency and tuning the second tuning circuit to an eighth frequency.

10. The system of claim 9 wherein the first and second tuning circuits each include:

a ferroelectric (FE) dielectric material having a variable dielectric constant responsive to a control voltage; and

,

an interface to receive the control voltage.

11. The system of claim 10 wherein the first and second tuning circuits are responsive to control voltages in the range of zero to three volts dc.

12. The system of claim 10 wherein the first and second tuning circuits include a ferroelectric variable capacitor selected from the group including interdigital, gap, and overlay capacitors

13. The system of claim 9 wherein the first tuning circuit includes:

a first inductor with a fixed inductance value;

a first variable capacitor with a selectable capacitance value; and

,

wherein the second tuning circuit includes;

a second inductor with a fixed inductance value;

a second variable capacitor with a selectable capacitance value.

14. The system of claim 13 wherein the first variable capacitor has a first terminal connected to the sub-band matching circuit output port;

wherein the first inductor is connected in shunt between a second terminal of the first variable capacitor and a reference voltage;

wherein the second variable capacitor has a first terminal connected to the first variable capacitor second terminal; and

,

wherein the second inductor is connected in series between a second terminal of the second variable capacitor and a sub-band matching circuit input port.

15. The system of claim 14 wherein the first inductor has an inductance of 8 nano-Henrys (nH);

wherein the first variable capacitor has a capacitance in the range between 2.35 and 3.1 picofarads (pF);

wherein the second inductor has an inductance of 2 nH; and

,

wherein the second variable capacitor has a capacitance in the range between 1.85 and 3.5 pF.

16. The system of claim 15 wherein the first tuning circuit first frequency is responsive to a first variable capacitor value of 2.35 pF, and the second tuning circuit second frequency is responsive to a second variable capacitor value of 2.9 pF;

and,

wherein the first tuning circuit third frequency is responsive to a first variable capacitor value of 2.6 pF, and the second tuning circuit fourth frequency is responsive to a second capacitor value of 2.6 pF;

wherein the first tuning circuit fifth frequency is responsive to a first variable capacitor value of 3.1 pF, and the second tuning circuit sixth frequency is responsive to a second capacitor value of 1.85 pF; and

,

wherein the first tuning circuit seventh frequency is responsive to a first variable capacitor value of 2.6 pF, and the second tuning circuit eighth frequency is responsive to a second capacitor value of 3.5 pF.

17. The system of claim 3 wherein the sub-band matching circuit supplies the conjugate impedance at a first communication band in the range between 824 and 894 megahertz (MHz) and at a second communication band in the range of 1850 and 1990 MHz.

18. The system of claim 16 wherein the sub-band matching circuit supplies the conjugate impedance, with a return loss of less than 2:

1, at a first communication band sub-band of approximately 45 megahertz (MHz) and at a second communication band sub-band of approximately 80 MHz.

19. The system of claim 3 wherein the sub-band matching circuit supplies the conjugate impedance at a plurality of sub-bands in the first communication band and at a plurality of sub-bands in the second communication band.

20. The system of claim 1 wherein the dual-band matching circuit is a matching topology selected from the group including a tunable series element, a tunable shunt element, “

L”

, π

, “

T”

, and combinations of the above-mentioned topologies.

21. A wireless communications device with a bandwidth segment antenna matching system, the device comprising:

a transceiver having a wireless communications port to communicate information in a first communication band;

an antenna having an interface port with a frequency-dependent impedance;

a sub-band matching circuit including an input port connected to the transceiver wireless communications port and an output port connected to the antenna interface port selectively supplying a conjugate impedance at a sub-band of the first communication band.

22. The device of claim 21 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the first communication band and at a high end of the first communication band.

23. The device of claim 22 wherein the transceiver communicates information in a second communication band;

and,

wherein the sub-band matching circuit supplies a conjugate impedance at a sub-band of a second communication band.

24. The device of claim 23 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the second communication band and at a high end of the second communication band.

25. The device of claim 24 wherein the sub-band matching circuit includes:

a first tuning circuit; and

,

a second tuning circuit.

26. The device of claim 25 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the first communication band in response to tuning the first tuning circuit to a first frequency and tuning the second tuning circuit to a second frequency.

27. The device of claim 26 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a high end of the first communication band in response to tuning the first tuning circuit to a third frequency and tuning the second tuning circuit to a fourth frequency.

28. The device of claim 27 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a low end of the second communication band in response to tuning the first tuning circuit to a fifth frequency and tuning the second tuning circuit to a sixth frequency.

29. The device of claim 28 wherein the sub-band matching circuit selectively supplies the conjugate impedance at a high end of the second communication band in response to tuning the first tuning circuit to a seventh frequency and tuning the second tuning circuit to an eighth frequency.

30. The device of claim 29 wherein the first and second tuning circuits each include:

a ferroelectric (FE) dielectric material having a variable dielectric constant responsive to a control voltage; and

,

an interface to receive the control voltage.

31. The device of claim 30 wherein the first and second tuning circuits are responsive to control voltages in the range of zero to three volts dc.

32. The device of claim 30 wherein the first and second tuning circuits include a ferroelectric variable capacitor selected from the group including interdigital, gap, and overlay capacitors

33. The device of claim 29 wherein the first tuning circuit includes:

a first inductor with a fixed inductance value;

a first variable capacitor with a selectable capacitance value; and

,

wherein the second tuning circuit includes;

a second inductor with a fixed inductance value;

a second variable capacitor with a selectable capacitance value.

34. The device of claim 33 wherein the first variable capacitor has a first terminal connected to the sub-band matching circuit output port;

wherein the first inductor is connected in shunt between a second terminal of the first variable capacitor and a reference voltage;

wherein the second variable capacitor has a first terminal connected to the first variable capacitor second terminal; and

,

wherein the second inductor is connected in series between a second terminal of the second variable capacitor and a sub-band matching circuit input port.

35. The device of claim 34 wherein the first inductor has an inductance of 8 nano-Henrys (nH);

wherein the first variable capacitor has a capacitance in the range between 2.35 and 3.1 picofarads (pF);

wherein the second inductor has an inductance of 2 nH; and

,

wherein the second variable capacitor has a capacitance in the range between 1.85 and 3.5 pF.

36. The device of claim 35 wherein the first tuning circuit first frequency is responsive to a first variable capacitor value of 2.35 pF, and the second tuning circuit second frequency is responsive to a second variable capacitor value of 2.9 pF;

and,

wherein the first tuning circuit third frequency is responsive to a first variable capacitor value of 2.6 pF, and the second tuning circuit fourth frequency is responsive to a second capacitor value of 2.6 pF;

wherein the first tuning circuit fifth frequency is responsive to a first variable capacitor value of 3.1 pF, and the second tuning circuit sixth frequency is responsive to a second capacitor value of 1.85 pF; and

,

wherein the first tuning circuit seventh frequency is responsive to a first variable capacitor value of 2.6 pF, and the second tuning circuit eighth frequency is responsive to a second capacitor value of 3.5 pF.

37. The device of claim 23 wherein the sub-band matching circuit supplies the conjugate impedance at a first communication band in the range between 824 and 894 megahertz (MHz) and at a second communication band in the range of 1850 and 1990 MHz.

38. The device of claim 37 wherein the sub-band matching circuit supplies the conjugate impedance, with a return loss of less than 2:

1, at a first communication band sub-band of approximately 45 megahertz (MHz) and at a second communication band sub-band of approximately 80 MHz.

39. The device of claim 23 wherein the sub-band matching circuit supplies the conjugate impedance at a plurality of sub-bands in the first communication band and at a plurality of sub-bands in the second communication band.

40. The device of claim 21 wherein the dual-band matching circuit is a matching topology selected from the group including a tunable series element, a tunable shunt element, “

L”

, π

, “

T”

, and combinations of the above-mentioned topologies.

41. A method for sub-band impedance matching an antenna, the method comprising:

accepting a frequency-dependent impedance from an antenna; and

,

selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band.

42. The method of claim 41 further comprising:

selectively supplying a conjugate impedance match for the antenna at a sub-band of a second communication band.

43. The method of claim 42 further comprising:

tuning a first tuning circuit to a first frequency;

simultaneously tuning a second tuning circuit to a second frequency; and

,

wherein selectively supplying a conjugate impedance for matching the antenna at a sub-band of the first communication band includes matching the antenna at a low end of the first communication band in response to the first and second frequencies.

44. The method of claim 43 wherein tuning the first tuning circuit includes tuning to a third frequency;

wherein simultaneously tuning the second tuning circuit includes tuning to a fourth frequency; and

,

wherein selectively supplying a conjugate impedance for matching the antenna at a sub-band of the first communication band includes matching the antenna at a high end of the first communication band in response to the third and fourth frequencies.

45. The method of claim 44 wherein tuning the first tuning circuit includes tuning to a fifth frequency;

wherein simultaneously tuning the second tuning circuit includes tuning to a sixth frequency; and

,

wherein selectively supplying a conjugate impedance for matching the antenna at a sub-band of the second communication band includes matching the antenna at a low end of the second communication band in response to the fifth and sixth frequencies.

46. The method of claim 45 wherein tuning the first tuning circuit includes tuning to a seventh frequency;

wherein simultaneously tuning the second tuning circuit includes tuning to an eighth frequency; and

,

wherein selectively supplying a conjugate impedance for matching the antenna at a sub-band of the second communication band includes matching the antenna at a high end of the second communication band in response to the seventh and eighth frequencies.

47. The method of claim 46 wherein tuning the first and second tuning circuits includes:

accepting first and second control voltages, respectively, for the first and second tuning circuits; and

,

adjusting the dielectric constant of a ferroelectric (FE) dielectric material in response to the control voltages.

48. The method of claim 47 wherein accepting first and second control voltages includes accepting control voltages in the range between zero and 3 volts dc.

49. The method of claim 46 wherein tuning the first tuning circuit includes tuning a first variable capacitor, with a selectable capacitance value, connected to a first inductor with a fixed inductance value;

and,

wherein tuning the second tuning circuit includes tuning a second variable capacitor, with a selectable capacitance value, connected to a second inductor with a fixed inductance value.

50. The method of claim 49 wherein tuning the first tuning circuit includes tuning a first variable capacitor, with a selectable capacitance in the range between 2.35 and 3.1 picofarads (pF), connected to a first inductor with a fixed inductance value of 8 nano-Henrys (nH);

and,

wherein tuning the second tuning circuit includes tuning a second variable capacitor, with a selectable capacitance value in the range of 1.85 and 3.5 pF, connected to a second inductor with a fixed inductance value of 2 nH.

51. The method of claim 50 wherein tuning the first tuning circuit includes tuning the first variable capacitor to:

the first frequency at a capacitor value of 2.35 pF;

the third frequency at a capacitor value of 2.6 pF;

the fifth frequency at a capacitor value of 3.1 pF;

the seventh frequency at a capacitor value of 2.6 pF; and

,

wherein tuning the second tuning circuit includes tuning the second variable capacitor to;

the second frequency at a capacitor value of 2.9 pF;

the fourth frequency at a capacitor value of 2.6 pF;

the sixth frequency at a capacitor value of 1.85 pF; and

,

the eighth frequency at a capacitor value of 3.5 pF.

52. The method of claim 51 wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band includes matching the antenna for a first communication band in the range of 824 to 894 MHz;

and,

wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a second communication band includes matching the antenna for a second communication band in the range of 1850 to 1990 MHz.

53. The method of claim 52 wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band includes matching the antenna with a return loss of less than 2:

1 across a sub-band of approximately 45 MHz; and

,

wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a second communication band includes matching the antenna with a return loss of less than 2;

1 across a sub-band of approximately 80 MHz.

54. The method of claim 42 wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a first communication band includes matching the antenna at a plurality of sub-bands in the first communication band;

and,

wherein selectively supplying a conjugate impedance match for the antenna at a sub-band of a second communication band includes matching the antenna at a plurality of sub-bands in the second communication band.