Millimeter wave pulsed radar system
View Patent ↗A millimeter wave pulsed radar system includes a radar synthesizer having a voltage controlled oscillator/phase locked loop (VCO/PLL) circuit, direct digital synthesizer (DDS) circuit and quadrature modulator circuit that are operative to generate an intermediate frequency local oscillator signal (IF/LO signal). A radar transceiver is operative with the radar synthesizer for receiving the IF/LO signal. A transmitter section has a frequency multiplier that multiplies the IF/LO signal up to a millimeter wave (MMW) radar signal and a receiver section and includes a direct conversion mixer that receives a MMW radar signal and the IF/LO signal to produce I/Q baseband signals that are later digitized and processed.
1. A millimeter wave pulsed radar system comprising:
a radar synthesizer comprising a voltage controlled oscillator/phase locked loop (VCO/PLL) circuit that outputs a fixed frequency signal, a direct digital synthesizer (DDS) circuit that generates in-phase and quadrature signals (I/Q signals), and a quadrature modulator circuit that receives the fixed frequency signal and I/Q signals and generates a signal operative as an intermediate frequency and local oscillator signal (IF/LO signal); and
a radar transceiver operative with the radar synthesizer for receiving the IF/LO signal, and comprising a transmitter section having a frequency multiplier that multiplies the IF/LO signal up to a millimeter wave (MMW) radar signal, and a receiver section that receives a MMW radar signal, including a direct conversion mixer that receives the MMW radar signal and the IF/LO signal to produce I/Q baseband signals that are later digitized and processed.
2. A millimeter wave pulsed radar system according to claim 1 , and further comprising a reference clock, wherein said VCO/PLL circuit and DDS circuit are phase locked to said reference clock.
3. A millimeter wave pulsed radar system according to claim 1 , wherein said radar synthesizer comprises a frequency multiplier that receives the IF/LO signal and multiplies the IF/LO signal up to about 8 to about 15 Gigahertz.
4. A millimeter wave pulsed radar system according to claim 1 , wherein said radar transceiver is operative for transmitting and receiving Ka-band signals.
5. A millimeter wave pulsed radar system according to claim 1 , and further comprising an analog-to-digital (A/D) converter that receives the I/Q baseband signals to produce digitized I/Q data, and a processor for receiving said digitized I/Q data and providing image rejection.
6. A millimeter wave pulsed radar system according to claim 5 , wherein said processor is operative for implementing a digital correction by injecting a signal at an amplifier input and measuring I/Q gain and phase balance to produce a correction term that is updated over temperature.
7. A millimeter wave pulsed radar system according to claim 1 , wherein said transmitter section comprises a driver amplifier and high power amplifier that are operative during transmitter operation and inoperative during receiver operation.
8. A millimeter wave pulsed radar system according to claim 1 , wherein said radar transceiver comprises a power divider operative with said transmitter and receiver sections for receiving and dividing the IF/LO signal into respective transmitter and receiver sections.
9. A millimeter wave pulsed radar system according to claim 1 , wherein said radar transceiver further comprises a sum and difference antenna port and a transmit/receive switch and a sum/difference circuit operative with said transmitter and receiver section.
10. A millimeter wave pulsed radar system according to claim 1 , wherein said transmitter section further comprises a high power amplifier (HPA), and a gate driver and two-state analog switch circuit operative for pulsing the HPA and producing a pulsed MMW radar signal.
11. A millimeter wave pulsed radar system according to claim 1 , and further comprising a current boost circuit for supplying power to said radar transceiver, including an array of series connected capacitors, resistors and inductors.
12. A millimeter wave pulsed radar system according to claim 1 , wherein said direct conversion mixer comprises a sub-harmonic image reject mixer.
13. A millimeter wave pulsed radar system according to claim 1 , wherein said radar synthesizer is operative for pulse compression, including phase modulation and linear frequency modulation.
14. A millimeter wave pulsed radar system comprising:
a circuit card assembly having microwave monolithic integrated circuit (MMIC) chips and RF, power and control circuit components mounted thereon that form a radar synthesizer comprising a voltage controlled oscillator/phase locked loop (VCO/PLL) circuit, a direct digital synthesizer (DDS) circuit, and a quadrature modulator circuit that are operative with each other for generating an intermediate frequency and local oscillator signal (IF/LO signal), and a radar transceiver operative with the radar synthesizer for receiving the IF/LO signal, and comprising a transmitter section that multiples the IF/LO signal up to a millimeter wave (MMW) radar signal for transmission, and a receiver section that receives and mixes a MMW radar signal and the IF/LO signal and down converts the MMW radar signal to I/Q baseband signals that are later digitized and processed;
a base on which the circuit card assembly is positioned, including waveguide ports and a thermal path formed therein and positioned below any MMIC chips and circuit components that produce excess heat during operation; and
a substrate cover made of the same material as the circuit card assembly secured on the circuit card assembly and including metallization and RF channelization.
15. A millimeter wave pulsed radar system according to claim 14 , wherein said substrate cover and circuit card assembly are both formed from FR4 material.
16. A millimeter wave pulsed radar system according to claim 14 , wherein said circuit card assembly includes a top layer formed as a RF specific material.
17. A millimeter wave pulsed radar system according to claim 16 , wherein said RF specific material comprises Rogers material.
18. A millimeter wave pulsed radar system according to claim 14 , wherein said circuit card assembly includes a ground plane and heat spreader mounted under said MMIC chips.
19. A millimeter wave pulsed radar system according to claim 18 , wherein said circuit card assembly includes vias interconnecting said base and ground plane and heat spreader.
20. A millimeter wave pulsed radar system according to claim 14 , and further comprising a reference clock, wherein said VCO/PLL circuit and DDS circuit are phase locked to said reference clock.
21. A millimeter wave pulsed radar system according to claim 14 , wherein said radar synthesizer comprises a frequency multiplier that receives the IF/Lo signal and multiplies the signal up to about 8 to about 15 Gigahertz.
22. A millimeter wave pulsed radar system according to claim 14 , wherein said radar transceiver is operative for transmitting and receiving Ka-band signals.
23. A millimeter wave pulsed radar system according to claim 14 , and further comprising an analog-to-digital (A/D) converter that receives the I/Q baseband signals to produce digitized I/Q data and a processor for receiving said digitized I/Q data and providing image rejection.
24. A millimeter wave pulsed radar system according to claim 23 , wherein said processor is operative for implementing a digital correction by injecting a signal at an amplifier input and measuring I/Q gain and phase balance to produce a correction term that is updated over temperature.
25. A millimeter wave pulsed radar system according to claim 14 , wherein said transmitter section comprises a driver amplifier and high power amplifier that are operative during transmitter operation and inoperative during receiver operation.
26. A millimeter wave pulsed radar system according to claim 14 , wherein said radar transceiver comprises a power divider operative with said transmitter and receiver sections for receiving and dividing the IF/LO signal into respective transmitter and receiver sections.
27. A millimeter wave pulsed radar system according to claim 14 , wherein said radar transceiver further comprises a sum and difference antenna port and a transmit/receive switch and a sum/difference circuit operative with said transmitter and receiver sections.
28. A millimeter wave pulsed radar system according to claim 14 , wherein said transmitter section further comprises a high power amplifier (HPA), and a gate driver and two state analog switch circuit operative for pulsing the HPA and producing a pulsed MMW radar signal.
29. A millimeter wave pulsed radar system according to claim 14 , and further comprising a current boost circuit for supplying power to said radar transceiver, including an array of series connected capacitors, resistors and inductors.
30. A millimeter wave pulse radar system according to claim 14 , wherein said radar synthesizer is operative for pulse compression, including phase modulation and linear frequency modulation.