Harmonic matching network for a saturated amplifier
First Claim
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1. A transmitter power amplifier for converting power from a direct current (DC) supply to radio frequency power (RF) in a load resistance, comprising:
- an amplifier comprising at least one active output device, the amplifier having an output capacitance; and
a harmonic terminating and impedance matching network comprising a plurality of sections coupled between said amplifier and the load resistance, a first section nearest said amplifier creating an impedance at the at least one active output device which is resonant with said output capacitance at a highest harmonic frequency and compensates for said output capacitance to produce a high impedance at said highest harmonic frequency, and a second section nearest the load resistance creating an impedance at said at least one active output device which resonates with said output capacitance at a lowest harmonic frequency and compensates for said output capacitance to produce a high impedance at said lowest harmonic frequency.
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Abstract
Systems and methods for increasing the efficiency of direct current (DC) power to radio frequency (RF) power include a harmonic matching network that inhibits harmonic current flow for a number of harmonic frequencies. The matching network includes a number of sections, where each section generates an impedance that resonates with the output capacitance at a harmonic frequency. Each section of the matching network also creates a high impedance to the amplifier at the respective odd harmonic frequency.
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Citations
23 Claims
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1. A transmitter power amplifier for converting power from a direct current (DC) supply to radio frequency power (RF) in a load resistance, comprising:
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an amplifier comprising at least one active output device, the amplifier having an output capacitance; and
a harmonic terminating and impedance matching network comprising a plurality of sections coupled between said amplifier and the load resistance, a first section nearest said amplifier creating an impedance at the at least one active output device which is resonant with said output capacitance at a highest harmonic frequency and compensates for said output capacitance to produce a high impedance at said highest harmonic frequency, and a second section nearest the load resistance creating an impedance at said at least one active output device which resonates with said output capacitance at a lowest harmonic frequency and compensates for said output capacitance to produce a high impedance at said lowest harmonic frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
a number of intermediate sections located between the first and second sections, each intermediate section compensating for said output capacitance to produce a high impedance at an intermediate harmonic frequency between the highest and lowest harmonic frequencies, said intermediate harmonic frequency being higher for a section nearer said amplifier and being lower for a section nearer said load resistance.
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3. The transmitter power amplifier of claim 1, wherein said plurality of sections comprises two sections and terminates two odd harmonics.
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4. The transmitter power amplifier of claim 1, wherein said lowest harmonic frequency is a third harmonic.
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5. The transmitter power amplifier of claim 1, wherein said at least one active output device forms a single-ended amplifier and said harmonic terminating and impedance matching network produces high impedance at said at least one active output device for at least two odd harmonics and a low impedance at a second harmonic.
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6. The transmitter power amplifier of claim 1, wherein each of said plurality of sections transforms a resistive impedance at its respective input at the fundamental frequency to a resistive impedance at its respective output.
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7. The transmitter power amplifier of claim 6, wherein said at least one active output device forms a single-ended amplifier and said harmonic terminating and impedance matching network produces high impedance at said at least one active output device for a third harmonic and a low impedance at a second harmonic.
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8. The transmitter power amplifier of claim 1, wherein said at least one active output device comprises a push-pull amplifier.
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9. The transmitter power amplifier of claim 1, wherein said at least one active output device is biased to consume a non-zero quiescent current from said DC supply to produce a substantially linear output in relation to an amplifier input signal.
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10. The transmitter power amplifier of claim 9, wherein the amplifier predistorts the amplitude of the amplifier input signal to produce amplified signals that follow a desired amplitude modulation.
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11. The transmitter power amplifier of claim 1, wherein said harmonic termination and impedance matching network comprises alternating series inductors and shunt, series-resonant harmonic traps.
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12. The transmitter power amplifier of claim 1, wherein said harmonic termination and impedance matching network comprises alternating series inductors and shunt, open-circuit stub traps.
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13. The transmitter power amplifier of claim 1, wherein said harmonic terminating network comprises sections of transmission lines alternating with shunt open-circuit stub traps.
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14. The transmitter power amplifier of claim 1, wherein each of the plurality of sections comprises a series element and a shunt element.
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15. The transmitter power amplifier of claim 14, wherein said series element comprises at least one of a transmission line section and a series inductor.
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16. The transmitter power amplifier of claim 14, wherein said shunt element comprises at least one of a series-resonant trap and an open-circuit transmission-line stub trap.
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17. In a mobile terminal comprising an amplifier having an output capacitance, a method comprising:
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converting power from a direct current (DC) power supply to radio frequency (RF) power, via the amplifier;
creating a first impedance at an output of the amplifier, the first impedance resonating with the output capacitance at a first harmonic frequency and compensating for the output capacitance to produce a high impedance at the first harmonic frequency; and
creating a second impedance at the output of the amplifier, the second impedance resonating with the output capacitance of the amplifier at a second harmonic frequency and compensating for the output capacitance to produce a high impedance at the second harmonic frequency. - View Dependent Claims (18, 19, 20, 21)
outputting the RF power to a transmit device.
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20. The method of claim 17, further comprising:
generating a plurality of impedances at the output of the amplifier, each of the plurality of impedances resonating with the output capacitance at a respective harmonic frequency between the first and second harmonic frequencies.
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21. The method of claim 20, further comprising:
producing a high impedance at each respective harmonic frequency including the effects of the output capacitance.
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22. A class-F amplifier, comprising:
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an input receiving a sinusoidal drive signal;
at least one active output device receiving the sinusoidal drive signal, the at least one active output device being forward-biased with a predetermined current; and
a harmonic network coupled to the at least one active output device, the harmonic network terminating odd harmonic frequencies to generate a substantially square wave output voltage signal waveform and sinusoidal output current waveform, wherein the predetermined current is sufficient to substantially reduce distortion in the substantially square wave output voltage waveform in the vicinity of zero crossings of the output current waveform.
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23. A mobile terminal, comprising:
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an amplifier that converts power from a direct current (DC) power supply to radio frequency power (RF), the amplifier having an output capacitance;
a circuit coupled to the amplifier, the circuit comprising a plurality of sections, each section comprising at least one element that generates an impedance that resonates with the output capacitance at one of a number of respective odd harmonic frequencies and creates a high impedance to the amplifier at the respective odd harmonic frequency; and
a transmit device coupled to the circuit, the transmit device receiving the RF power.
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Specification