US5553319A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Routing YIG-tuned mixer
Assignee: Agilent Technologies Inc
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Filing: 1995-01-23
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Granted: 1996-09-03
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Expires: 2015-01-23
Abstract
Abstract A routing YIG-tuned resonator filter integrated with an image-enhanced, double-balanced mixer. The YIG-tuned resonator filter is preferably a four-sphere YIG-tuned preselector which is integrated with a low-loss, fundamentally or harmonically mixed, image-enhanced, double-balanced mixer to provide a high level of dynamic range in a harmonically mixed front end. An input resonator of the preselector in combination with a dual PIN diode switch switches low-frequency input signals (e.g., 0 to 2.9 GHz) to a low-band mixer. For RF input signals (e.g., 2.7 to 26.5 GHz), the four-sphere YIG-tuned preselector is combined with the image-enhanced, double-balanced mixer which incorporates a GaAs monolithic diode bridge integrated circuit. This provides a cost effective front end for a microwave spectrum analyzer.
Inventors
- 👤 Hassan Tanbakuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:36
CPC Classifications
H; H03; H03D; H03D7/00; H03D7/14; H03D7/1408; H03D9/00; H03D9/06; H03D9/0608; H03J; H03J3/00; H03J3/02; H03J3/16
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
344 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being terminated at a first end by a first intermediate-frequency (IF) balun having an input connected to the first end of the output coupling loop to provide an even harmonic IF balun, the output of the first IF balun being connected to an even IF port, and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; first and second capacitors connected between the respective junctions of the output coupling loop and the first IF balun, on the one hand, and ground, on the other hand; third and fourth capacitors connected in series across the outputs of the diode bridge; a swept local oscillator (LO) input for generating an LO signal, the junction between the third and fourth capacitors being connected to the LO input; first and second inductors having first ends connected to the respective junctions of the diode bridge and the third and fourth capacitors, respectively; and a second IF balun having an input connected across second ends of the first and second inductors to provide a fundamental and odd harmonic IF balun, an output of the second IF balun being connected to an odd IF port; wherein the frequency-tunable resonator filter and mixer provides one of odd and even harmonic mixing.
Claim 2
Dependent Claim
344 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being terminated at a first end by a first intermediate-frequency (IF) balun having an input connected to the first end of the output coupling loop to provide an even harmonic IF balun, the output of the first IF balun being connected to an even IF port, and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; first and second capacitors connected between the respective junctions of the output coupling loop and the first IF balun, on the one hand, and ground, on the other hand; third and fourth capacitors connected in series across the outputs of the diode bridge; a swept local oscillator (LO) input for generating an LO signal, the junction between the third and fourth capacitors being connected to the LO input; first and second inductors having first ends connected to the respective junctions of the diode bridge and the third and fourth capacitors, respectively; and a second IF balun having an input connected across second ends of the first and second inductors to provide a fundamental and odd harmonic IF balun, an output of the second IF balun being connected to an odd IF port; wherein the frequency-tunable resonator filter and mixer provides one of odd and even harmonic mixing.
Claim 3
Dependent Claim
252 words
The frequency-tunable resonator filter and mixer in accordance with claim 1, further comprising a routing circuit for routing low-frequency input signals to a low-frequency output and high-frequency input signals to the output coupling loop, wherein the input coupling loop has a first end coupled to the RF input and a second end, the routing circuit comprising: a first transmission line and a second transmission line connected in series between the second end of the input coupling loop and the low-frequency output; a fifth capacitor and a first diode connected in series between ground and the junction of the RF input and first transmission line; a sixth capacitor and a second diode connected in series between ground and the junction of the first and second transmission lines; and a bias network, comprising: a first resistor having a first end connected to the junction of the fifth capacitor and first diode and a second resistor having a first end connected to the junction of the sixth capacitor and second diode, each of the first and second resistors having a second end connected to a first end of a third resistor; a third inductor having a first end connected to a second end of the third resistor; a seventh capacitor connected between a second end of the third inductor and ground; and a bias voltage selectively connected to the second end of the third inductor for simultaneously biasing the first and second diodes "on" to route the high-frequency input signals to the output coupling loop.
Claim 4
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 2, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 5
Dependent Claim
85 words
The frequency-tunable resonator filter and mixer in accordance with claim 2, wherein the output coupling loop is terminated at the first end by an eighth capacitor connected in parallel with the input of the first IF balun, further comprising: a ninth capacitor connected across the diode bridge; and tenth and eleventh capacitors connected between the respective junctions of the first inductor and the second IF balun and the second inductor and the second IF balun, on the one hand, and ground, on the other hand.
Claim 6
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 4, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 7
Dependent Claim
85 words
The frequency-tunable resonator filter and mixer in accordance with claim 1, wherein the output coupling loop is terminated at the first end by a fifth capacitor connected in parallel with the input of the first IF balun, further comprising: a sixth capacitor connected across the diode bridge; and seventh and eighth capacitors connected between the respective junctions of the first inductor and the second IF balun and the second inductor and the second IF balun, on the one hand, and ground, on the other hand.
Claim 8
Dependent Claim
38 words
The frequency-tunable resonator filter and mixer in accordance with claim 6, further comprising: an IF switch for selectively switching to one of the odd and even IF ports to provide one of odd and even harmonic mixing, respectively.
Claim 9
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 7, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 10
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 6, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 11
Dependent Claim
38 words
The frequency-tunable resonator filter and mixer in accordance with claim 1, further comprising: an IF switch for selectively switching to one of the odd and even IF ports to provide one of odd and even harmonic mixing, respectively.
Claim 12
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 1, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 13
Dependent Claim
273 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being continuous at a first end and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; a swept local oscillator (LO) input connected to the first end of the output coupling loop for generating an LO signal; an intermediate-frequency (IF) balun having an input connected across the diode bridge to provide a fundamental and odd harmonic IF balun, an output of the IF balun being connected to an odd IF port; and first and second capacitors connected between the respective junctions of the diode bridge and the IF balun, on the one hand, and ground, on the other hand; wherein the frequency-tunable resonator filter and mixer mixes one of a fundamental and odd harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 14
Dependent Claim
273 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being continuous at a first end and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; a swept local oscillator (LO) input connected to the first end of the output coupling loop for generating an LO signal; an intermediate-frequency (IF) balun having an input connected across the diode bridge to provide a fundamental and odd harmonic IF balun, an output of the IF balun being connected to an odd IF port; and first and second capacitors connected between the respective junctions of the diode bridge and the IF balun, on the one hand, and ground, on the other hand; wherein the frequency-tunable resonator filter and mixer mixes one of a fundamental and odd harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 15
Dependent Claim
249 words
The frequency-tunable resonator filter and mixer in accordance with claim 12, further comprising a routing circuit for routing low-frequency input signals to a low-frequency output and high-frequency input signals to the output coupling loop, wherein the input coupling loop has a first end coupled to the RF input and a second end, the routing circuit comprising: a first transmission line and a second transmission line connected in series between the second end of the input coupling loop and the low-frequency output; a third capacitor and a first diode connected in series between ground and the junction of the RF input and first transmission line; a fourth capacitor and a second diode connected in series between ground and the junction of the first and second transmission lines; and a bias network, comprising: a first resistor having a first end connected to the junction of the third capacitor and first diode and a second resistor having a first end connected to the junction of the fourth capacitor and second diode, each of the first and second resistors having a second end connected to a first end of a third resistor; an inductor having a first end connected to a second end of the third resistor; a fifth capacitor connected between a second end of the inductor and ground; and a bias voltage selectively connected to the second end of the inductor for simultaneously biasing the first and second diodes "on" to route the high-frequency input signals to the output coupling loop.
Claim 16
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 12, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 17
Dependent Claim
21 words
The frequency-tunable resonator filter and mixer in accordance with claim 12, further comprising: a third capacitor connected across the diode bridge.
Claim 18
Dependent Claim
292 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being continuous at a first end and connected to ground and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; first and second capacitors connected in series across the diode bridge; a swept local oscillator (LO) input for generating an LO signal, the junction between the first and second capacitors being connected to the LO input; first and second inductors having first ends connected to the respective junctions of the diode bridge and the first and second capacitors; and an intermediate-frequency (IF) balun having an input connected across second ends of the first and second inductors to provide a fundamental and odd harmonic IF balun, an output of the IF balun being connected to an odd IF port; wherein the frequency-tunable resonator filter and mixer mixes one of a fundamental and odd harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 19
Dependent Claim
292 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being continuous at a first end and connected to ground and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; first and second capacitors connected in series across the diode bridge; a swept local oscillator (LO) input for generating an LO signal, the junction between the first and second capacitors being connected to the LO input; first and second inductors having first ends connected to the respective junctions of the diode bridge and the first and second capacitors; and an intermediate-frequency (IF) balun having an input connected across second ends of the first and second inductors to provide a fundamental and odd harmonic IF balun, an output of the IF balun being connected to an odd IF port; wherein the frequency-tunable resonator filter and mixer mixes one of a fundamental and odd harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 20
Dependent Claim
252 words
The frequency-tunable resonator filter and mixer in accordance with claim 16, further comprising a routing circuit for routing low-frequency input signals to a low-frequency output and high-frequency input signals to the output coupling loop, wherein the input coupling loop has a first end coupled to the RF input and a second end, the routing circuit comprising: a first transmission line and a second transmission line connected in series between the second end of the input coupling loop and the low-frequency output; a third capacitor and a first diode connected in series between ground and the junction of the RF input and first transmission line; a fourth capacitor and a second diode connected in series between ground and the junction of the first and second transmission lines; and a bias network, comprising: a first resistor having a first end connected to the junction of the third capacitor and first diode and a second resistor having a first end connected to the junction of the fourth capacitor and second diode, each of the first and second resistors having a second end connected to a first end of a third resistor; a third inductor having a first end connected to a second end of the third resistor; a fifth capacitor connected between a second end of the third inductor and ground; and a bias voltage selectively connected to the second end of the third inductor for simultaneously biasing the first and second diodes "on" to route the high-frequency input signals to the output coupling loop.
Claim 21
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 16, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 22
Dependent Claim
40 words
The frequency-tunable resonator filter and mixer in accordance with claim 16, further comprising: a third capacitor connected across the diode bridge; and fourth and fifth capacitors connected between the second ends of the first and second inductors, respectively, and ground.
Claim 23
Dependent Claim
268 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being terminated at a first end by an intermediate-frequency (IF) balun having an input connected to the first end of the output coupling loop to provide an even harmonic IF balun, an output of the IF balun being connected to an even IF port, and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; a swept local oscillator (LO) input connected across the diode bridge for generating an LO signal; and first and second capacitors connected between the respective junctions of the output coupling loop and the IF balun, on the one hand, and ground, on the other hand; wherein the frequency-tunable resonator filter and mixer mixes even harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 24
Dependent Claim
268 words
A frequency-tunable resonator filter and mixer to provide a tunable bandpass filter and image-enhanced, double-balanced mixer in response to a radio-frequency (RF) input signal having a given frequency at an RF input, comprising: at least one frequency-tunable resonator, comprising: an input coupling loop coupled to the RF input for receiving the RF input signal; a ferrimagnetic sphere proximate to the input coupling loop; and an output coupling loop proximate to the ferrimagnetic sphere for receiving the RF input signal when a resonance frequency of the at least one frequency-tunable resonator approximates the given frequency of the RF input signal, the output coupling loop being terminated at a first end by an intermediate-frequency (IF) balun having an input connected to the first end of the output coupling loop to provide an even harmonic IF balun, an output of the IF balun being connected to an even IF port, and the output coupling loop being terminated at a second end by a diode bridge comprising four diodes; an electromagnet for producing a DC magnetic field that is uniform over the at least one frequency-tunable resonator for tuning the resonance frequency of the at least one frequency-tunable resonator; a swept local oscillator (LO) input connected across the diode bridge for generating an LO signal; and first and second capacitors connected between the respective junctions of the output coupling loop and the IF balun, on the one hand, and ground, on the other hand; wherein the frequency-tunable resonator filter and mixer mixes even harmonic products of the LO signal with the RF input signal to produce a predetermined low-frequency IF signal output.
Claim 25
Dependent Claim
249 words
The frequency-tunable resonator filter and mixer in accordance with claim 20, further comprising a routing circuit for routing low-frequency input signals to a low-frequency output and high-frequency input signals to the output coupling loop, wherein the input coupling loop has a first end coupled to the RF input and a second end, the routing circuit comprising: a first transmission line and a second transmission line connected in series between the second end of the input coupling loop and the low-frequency output; a third capacitor and a first diode connected in series between ground and the junction of the RF input and first transmission line; a fourth capacitor and a second diode connected in series between ground and the junction of the first and second transmission lines; and a bias network, comprising: a first resistor having a first end connected to the junction of the third capacitor and first diode and a second resistor having a first end connected to the junction of the fourth capacitor and second diode, each of the first and second resistors having a second end connected to a first end of a third resistor; an inductor having a first end connected to a second end of the third resistor; a fifth capacitor connected between a second end of the inductor and ground; and a bias voltage selectively connected to the second end of the inductor for simultaneously biasing the first and second diodes "on" to route the high-frequency input signals to the output coupling loop.
Claim 26
Dependent Claim
152 words
The frequency-tunable resonator filter and mixer in accordance with claim 20, further comprising: a second frequency-tunable resonator having an input coupled to the RF input and an output to provide a first stage of the filter; a third frequency-tunable resonator having an input coupled to the output of the second frequency-tunable resonator and an output to provide a second stage of the filter; and a fourth frequency-tunable resonator having an input coupled to the output of the third frequency-tunable resonator and an output to provide a third stage of the filter; wherein the electromagnet produces a DC magnetic field that is uniform over the frequency-tunable resonators for tuning the resonance frequency of the resonators; and wherein the input coupling loop of the at least one frequency-tunable resonator is coupled to the output of the fourth frequency-tunable resonator to provide a fourth stage of the filter, as well as an image-enhanced, double-balanced mixer.
Claim 27
Dependent Claim
26 words
The frequency-tunable resonator filter and mixer in accordance with claim 20, wherein the output coupling loop is terminated at the first end by a third capacitor.
References Cited (Backward Citations)
US3947782A
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