# US 7,609,196 B2 · Method and device for imaging test objects by means of electromagnetic waves, in particular for inspecting individuals for suspicious items

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- Number: US 7,609,196 B2
- Document ID: US7609196B2
- Status: Granted
- Kind: B2
- Application number: 12/044,218
- Filed: 2008-03-07
- Published: 2008-09-04
- Granted: 2009-10-27
- Earliest claimed: 2005-09-07
- Assignees: Smiths Heimann GmbH
- Inventors: Michael Jeck; Frank Gumbmann; Lorenz-Peter Schmidt; Hue-Phat Tran; Jochen Weinzierl
- Web page: https://patentgrep.com/patent/US7609196B2

## CPC

- G01S 13/887: {for detection of concealed objects, e.g. contraband or weapons}
- G01S 13/02: Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S 13/90: using synthetic aperture techniques {, e.g. synthetic aperture radar [SAR] techniques}
- G01S 13/9082: {Rotating SAR [ROSAR]}
- H01Q 3/08: for varying two co-ordinates of the orientation
- G01S 13/9088: {Circular SAR [CSAR, C-SAR]}
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A method for imaging test objects by means of electromagnetic waves, in particular for the purpose of checking individuals for suspicious articles, in which method the test object is illuminated by electromagnetic waves, the scattered waves are received and evaluated for an imaginal representation of the test object on the basis of the synthetic aperture principle (SAR). A synthetic aperture is produced by the waves output by an antenna being concentrated initially in spatial terms, the point of high concentration being moved on a reflector along a circle.

## Claims

### Claim 1

A method for imaging test objects or inspecting individuals for suspicious items by electromagnetic waves, comprising the steps of
providing a synthetic aperture by first spatially concentrating electromagnetic waves emitted by an antenna to provide multiple locations of high concentration of said electromagnetic waves,
manipulating at least one location of high concentration to provide a moving virtual antenna;
illuminating a test object or individual with said moving virtual antenna of said electromagnetic waves; and
receiving and analyzing scattered electromagnetic waves resulting from said illuminating step using synthetic aperture imaging (SAR) to display an image of the test object.

### Claim 2 (depends on 1)

The method according to claim 1, wherein said electromagnetic waves comprise millimeter waves having a frequency between 1 GHz and 10 THz.

### Claim 3 (depends on 1)

The method according to claim 1, wherein parallel diverging cones of rays are sequentially produced by a quasi-optical element through rotation of the antenna.

### Claim 4 (depends on 1)

The method according to claim 1, wherein parallel diverging cones of rays with a changing angle of inclination are sequentially produced by a quasi-optical element through rotation of the antenna so that the cones of rays remain aimed at a substantially same point in space.

### Claim 5 (depends on 1)

The method according to claim 1, wherein said electromagnetic waves comprise millimeter waves having a frequency between 30 GHz and 300 GHz.

### Claim 6 (depends on 1)

The method according to claim 1, comprising projecting said electromagnetic waves emitted from said antenna onto a rotating component from which the waves are reflected and concentrated onto a reflector, wherein the reflector emits a moving, diverging cone of rays.

### Claim 7 (depends on 1)

The method according to claim 1, wherein said antenna which emits said electromagnetic waves is a rotatable antenna, and said electromagnetic waves are projected onto a focusing element, from which focusing element said electromagnetic waves are concentrated onto a quasi-optical element, and wherein the quasi-optical element emits a diverging cone of rays that are displaced in parallel during rotational motion of the virtual antenna.

### Claim 8 (depends on 1)

The method according to claim 1, wherein a virtual source is produced by a Nipkow disk, which covers a strip upon which the waves emitted by an antenna are focused.

### Claim 9 (depends on 1)

The method according to claim 1, wherein at least one transmitting antenna and at least one spatially separated receiving antenna are used to provide a moving virtual antenna.