Tunable matching circuit

• US 6,825,818 B2
• Filed: 08/10/2001
• Issued: 11/30/2004
• Est. Priority Date: 04/11/2001
• Status: Expired due to Term

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: Toncich, Stanley S.
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/927,136
• Publication Number:
  US 20020175878A1
• Time in Patent Office: 1,208 Days
• Field of Search: 343/707, 343/787, 343/700.MS, 343/753, 343/850, 343/860, 343/909, 333/125, 333/161, 333/205
• 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 capacitive element and an inductive element 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 capacitive element and an inductance value of the inductive element;

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 chance the impedance of the matching circuit; and

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.

2. 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.

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 0.25 GHz and 2.5 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 0.8 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 180 in a frequency range between 0.25 GHz and 7.0 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 about 0.8 GHz and 2.5 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 80 for a capacitance in a range between about 0.3 pF and 3.0 pF.

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 0.5 pF and 1.0 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 180 for a capacitance in a range between about 0.3 pF and 3.0 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 0.5 pF and 1.0 pF.

11. A communication device comprising:

a capacitive element and an inductive element 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 capacitive element and an inductance value of the inductive element;

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, and 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 a number representing 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 number representing the direct current voltage value.

12. A communication device comprising:

a capacitive element and an inductive element 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 capacitive element and an inductance value of the inductive element;

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, and

wherein the control source comprises a power detector which detects a power level of an RF signal and varics the control signal responsive to the power level of the RF signal.

13. A communication device comprising:

a capacitive element and an inductive element 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 capacitive element and an inductance value of the inductive element;

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;

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

a duplexer coupled to a second port of the matching circuit, and

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

14. A communication device comprising:

a capacitive element end an inductive element 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 capacitive element and an inductance value of the inductive element;

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;

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

a diplexer coupled to a second port of the matching circuit, and

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