Short pulse microwave transceiver
First Claim
1. A short pulse microwave transceiver apparatus comprising:
- a transmit clock for generating a transmit clock signal;
a pulsed transmit oscillator for producing transmitter RF bursts in response to the transmit clock signal;
a transmit antenna connected to the transmit oscillator to transmit the transmitter RF bursts;
a receive clock for generating a receive clock signal;
a pulsed local oscillator for generating gating RF bursts in response to the receive clock signal;
a harmonic sampler connected to the pulsed local oscillator;
a receive antenna connected to the harmonic sampler to receive RF bursts;
wherein the gating RF bursts from the pulsed local oscillator gate the harmonic sampler to detect RF bursts received by a receive antenna;
circuitry responsive to the harmonic sampler to provide a detected baseband output.
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Accused Products
Abstract
Harmonic techniques are employed to leverage low-cost, ordinary surface mount technology (SMT) to high microwave frequencies where tight beamforming with a small antenna makes reliable, high-accuracy pulse-echo radar systems possible. The implementation comprises a 24 GHz short-pulse transceiver comprised of a pulsed harmonic oscillator employed as a transmitter and an integrating, pulsed harmonic sampler employed as a receiver. The transmit oscillator generates a very short (0.5 ns) phase-coherent harmonic-rich oscillation at a sub-multiple of the actual transmitter frequency. A receiver local oscillator operates at a sub-multiple of the transmit frequency and is triggered with controlled timing to provide a very short (0.5 ns), phase-coherent local oscillator burst. The local oscillator burst is coupled to an integrating harmonic sampler to produce an integrated, equivalent-time replica of the received RF. The harmonic techniques overcome four major problems with non-harmonic approaches: 1) expensive, precision assembly, 2) high local oscillator noise, 3) sluggish oscillator startup, and 4) spurious local oscillator injection locking on external RF. The transceiver can be used for automotive backup and collision warning, precision radar rangefinding for fluid level sensing and robotics, precision radiolocation, wideband communications, and time-resolved holographic imaging.
215 Citations
45 Claims
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1. A short pulse microwave transceiver apparatus comprising:
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a transmit clock for generating a transmit clock signal;
a pulsed transmit oscillator for producing transmitter RF bursts in response to the transmit clock signal;
a transmit antenna connected to the transmit oscillator to transmit the transmitter RF bursts;
a receive clock for generating a receive clock signal;
a pulsed local oscillator for generating gating RF bursts in response to the receive clock signal;
a harmonic sampler connected to the pulsed local oscillator;
a receive antenna connected to the harmonic sampler to receive RF bursts;
wherein the gating RF bursts from the pulsed local oscillator gate the harmonic sampler to detect RF bursts received by a receive antenna;
circuitry responsive to the harmonic sampler to provide a detected baseband output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A short pulse microwave transmit oscillator comprising:
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a pulsed microwave oscillator operating at a sub-multiple of a transmit frequency;
an antenna connected to the oscillator, the antenna being resonant at the transmit frequency. - View Dependent Claims (19, 20)
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21. A short pulse microwave harmonic sampler comprising:
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a pulsed local oscillator;
anti-parallel detector diodes having first and second nodes;
an RF input coupled to the first node;
the pulsed local oscillator being coupled to the second node. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A short pulse microwave harmonic sampler comprising:
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a pulsed local oscillator;
a detector diode having first and second nodes;
an RF input connected to the first node;
the pulsed local oscillator being coupled to the second node. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A short pulse microwave oscillator comprising:
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an oscillator transistor having gate G, source S and drain D nodes;
an inductance connected between S and G;
a transmission line or wire shorter than one-quarter wavelength having a first and second end, with the first end connected to G and the second end coupled to D through stray capacitance. - View Dependent Claims (41, 42)
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43. A method of transmitting and receiving short microwave pulses, comprising:
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transmitting pulses from a first microwave oscillator;
pulsing a second microwave oscillator with controlled timing to gate a harmonic sampler;
sampling pulses transmitted from the first oscillator and reflected from an object with the harmonic sampler;
integrating two or more samples from the harmonic sampler. - View Dependent Claims (44)
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45. A method of transmitting and receiving short microwave pulses, comprising:
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operating a pulsed transmit oscillator at a first frequency;
coupling the pulsed transmit oscillator to a resonant antenna which is resonant at a second frequency which is a harmonic of the first frequency to produce a transmitted signal at the second frequency;
receiving a reflected signal at a resonant antenna which is resonant at the second frequency;
harmonically sampling the received signal with a third frequency which is a sub-harmonic of the second frequency.
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Specification