Video rate passive millimeter wave imaging system

• US 20050116947A1
• Filed: 12/23/2004
• Published: 06/02/2005
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Trex Enterprises Corporation
• Original Assignee: Trex Enterprises Corporation
• Inventors: Lovberg, John, Chedester, Richard, Kolinko, Vladimir
• Granted Patent: US 7,170,442 B2
• Time in Patent Office: Days
• US Class Current: 345/418
• CPC Class Codes: G01V 8/005 operating with millimetre waves, e.g. measuring the black losey radiation
• CPC Class Codes: H01Q 3/22 varying the orientation in accordance with variation of frequency of radiated wave
• CPC Class Codes: H01Q 3/2682 Time delay steered arrays

Abstract

A passive millimeter wave imaging system that includes at least one millimeter wave frequency scanning antenna and multiple beam formers collecting narrow beams of millimeter wave radiation from a two-dimensional field of view. The collected radiation is amplified and separated into bins corresponding to various vertical and horizontal beam orientations. In a preferred embodiment the beam formers include one phase processor and 192 frequency processors. Two dimensional images of a target are obtained by the simultaneous detection of signal power within each beam and converting it into pixel intensity level at a rate of 30 frames per second.

Claims

1. A video rate millimeter wave imaging device for producing video rate two-dimensional images, defining a first dimension and a second dimension comprising:

A) an antenna for collecting millimeter wave radiation from a field of view and directing that radiation into a first plurality of channels to produce high-frequency signals for each of said first plurality of channels,

B) a first array of low-noise MMIC amplifiers for amplifying the high-frequency signals, at frequencies higher than 60 GHz, in each of said first plurality of channels to produce a first plurality of amplified high-frequency signals,

C) a phase processor for processing said first plurality of amplified signals to produce a second plurality of signals in a second plurality of channels, each signal in said second plurality of signals being representative of an angular direction in said first dimension,

D) a second array of low-noise MMIC amplifiers for amplifying each of said second plurality of high-frequency signals, at frequencies higher than 60 GHz, in said second plurality of channels to produce a second plurality of amplified high-frequency signals,

E) a plurality of frequency processors, one for each channel of said second plurality of channels for processing said second plurality of amplified high-frequency signals, each frequency processor of said plurality of frequency processors, producing a plurality of high-frequency signals each of said high-frequency signals in said second plurality of high-frequency signals corresponding to a separate angular direction in said second dimension,

F) a plurality of detectors for detecting each of said plurality of high-frequency signals produced by each of said plurality of frequency processors, to produce a plurality of detector signals, and

G) electronic circuitry for converting said plurality of detector signals to two-dimensional images of said field of view at rates of 10 Hz or greater.

2. The device as in claim 1 wherein said antenna is a slotted flat panel antenna.

3. The device as in claim 1 wherein each amplifier in said first and second arrays of low-noise amplifiers are comprised of a plurality of MMIC amplifier units.

4. The device as in claim 2 wherein each of said MMIC amplifier units utilize a co-planer wave guide design on an indium phosphide substrate.

5. The device as in claim 2 wherein each amplifier in said first and second arrays of amplifiers are packaged together with other amplifiers in amplifier packages.

6. The device as in claim 2 wherein each package in said amplifier packages comprises eight amplifiers.

7. The device as in claim 3 wherein each amplifier in said first and second array of amplifiers comprise a band pass filter.

8. The device as in claim 3 wherein each MMIC amplifier unit comprises quarter wave lines terminated with bypass capacitors.

9. The device as in claim 1 wherein said phase processor comprises a Rotman type lens.

10. The device as in claim 1 wherein said frequency processor comprises a Rotman type lens.

11. The device as in claim 1 wherein said frequency processor comprises a Rotman type lens and said phase processor also comprises a Rotman type lens.

12. The device as in claim 1 wherein said first plurality of channels is about 232 channels, said second plurality of channels is about 192 channels and said plurality of high-frequency signals produced by each of said frequency processors is about 128 signals.

13. The device as in claim 1 wherein said electronic circuitry comprises readout chips, an electronics interface board and a personal computer.

14. The device as in claim 13 wherein said two-dimensional image is displayed on a computer monitor.