Tunable matching circuit

• US 20020175878A1
• Filed: 08/10/2001
• Published: 11/28/2002
• Est. Priority Date: 04/11/2001
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Toncich, Stanley S.
• Granted Patent: US 6,825,818 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: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/124 the means comprising a voltage dependent capacitance
• CPC Class Codes: H03B 5/1262 the means comprising switched elements
• CPC Class Codes: H03B 5/1293 having means for achieving a desired tuning characteristic, e.g. linearising the frequency characteristic across the tuning voltage range
• 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 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• 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 7/0123 : comprising distributed impedance elements together with lumped impedance elements
• CPC Class Codes: H03H 7/12 : Bandpass or bandstop filters with adjustable bandwidth and fixed centre frequency H03H7/09 takes precedence; automatic control of bandwidth in amplifiers H03G5/16
• CPC Class Codes: H03H 7/20 : Two-port phase shifters providing an adjustable phase shift
• 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
• CPC Class Codes: H04B 1/40 : Circuits

Abstract

The present invention provides for low loss tunable matching circuits at rf frequencies. Ferro-electric materials are used to produce low loss tunable capacitors and inductors for use in matching circuits.

Claims

1. A communication device comprising:

a capacitor and an inductor arranged as a matching circuit, the matching circuit having an impedance;

a ferro-electric material positioned to adjust a value that is a member of the group consisting of a capacitance value of the capacitor and an inductance value of the inductor;

a control line operably connected to the ferro-electric material;

a control source electrically connected to the control line, the control source configured to transmit a control signal on the control line;

wherein the ferro-electric material, responsive to the control signal, adjusts the value to change the impedance of the matching circuit.

2. The communication device of claim 1, wherein a wherein the quality factor of the matching circuit, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 in a frequency range between 0.25 GHz and 7.0 GHz.

3. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 in a frequency range between about 0.8 GHz and 7.0 GHz.

4. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 in a frequency range between about 0.25 GHz and 2.5 GHz.

5. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 in a frequency range between about 0.8 GHz and 2.5 GHz.

6. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 180 in a frequency range between 0.25 GHz and 7.0 GHZ.

7. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 180 in a frequency range between about 0.8 GHz and 2.5 GHz.

8. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 for a capacitance in a range between about 0.3 pF and 3.0 pF.

9. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 80 for a capacitance in a range between about 0.5 pF and 1.0 pF.

10. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 180 for a capacitance in a range between about 0.3 pF and 3.0 pF.

11. The communication device of claim 1, wherein the quality factor, when operated in a temperature range between about −

50 degrees Celsius and 100 degrees Celsius, is greater than about 180 for a capacitance in a range between about 0.5 pF and 1.0 pF.

12. The communication device of claim 1, wherein:

the control signal comprises a direct current voltage;

the control source is coupled to a band select signal, the band select signal comprising a signal identifying a band in which the matching circuit is to operate; and

the control source comprises;

a lookup table comprising the direct current voltage value corresponding to the band in which the matching circuit is to operate; and

a voltage source for generating the direct current voltage responsive to the direct current voltage value.

13. The communication device of claim 1, wherein the control source comprises a power detector which detects a power level of an RF signal and varies the control signal responsive to the power level of the RF signal.

14. The communication device of claim 1, wherein the control source comprises a lookup table and varies the control signal responsive to a value in the lookup table.

15. The communication device of claim 1, wherein the capacitive element comprises a capacitor and the inductive element comprises an inductor.

16. The communication device of claim 1, wherein:

the capacitive element is coupled between an input and an output; and

the inductive element is coupled between the output and ground.

17. The communication device of claim 1, wherein:

the inductive element is coupled between an input and ground; and

the capacitive element is coupled between the input and an output.

18. The communication device of claim 1, wherein:

the inductive element is coupled between an input and an output and

the capacitive element is coupled between the output and ground.

19. The communication device of claim 1, wherein:

the capacitive element is coupled between an input and ground; and

the inductive element is coupled between the input and an output.

20. The communication device of claim 1, wherein:

the capacitive element comprises a capacitor, the capacitor comprising a gap; and

the ferro-electric material is positioned in or near the gap for adjusting the capacitance value of the capacitor.

21. The communication device of claim 1, further comprising an amplifier coupled to the matching circuit.

22. The communication device of claim 21, wherein the amplifier is a low noise amplifier.

23. The communication device of claim 21, wherein the amplifier is a power amplifier.

24. The communication device of claim 1, further comprising:

an antenna coupled to a first port of the matching circuit; and

a duplexer coupled to a second port of the matching circuit.

25. The communication device of claim 1, further comprising:

an antenna coupled to a first port of the matching circuit; and

a diplexer coupled to a second port of the matching circuit.