Microwave holographic measuring method and apparatus

• US 6,825,674 B2
• Filed: 07/22/2003
• Issued: 11/30/2004
• Est. Priority Date: 09/13/2000
• Status: Expired due to Fees

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.), University of Northumbria At Newcastle
• Original Assignee: University of Northumbria At Newcastle
• Inventors: Smith, David
• Primary Examiner(s): Deb, Anjan
• Assistant Examiner(s): Benson, Walter
• Application Number:
  US10/380,562
• Publication Number:
  US 20040004568A1
• Time in Patent Office: 497 Days
• Field of Search: 324/637, 324/638, 324/639, 324/640, 342/188, 343/700.R
• US Class Current: 324/637
• CPC Class Codes: G01R 29/10 Radiation diagrams of antennas
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons

Abstract

A microwave holographic measuring method is disclosed. A first electrical signal S of microwave frequency is provided. A first part S1 of the first signal S is directed to a first antenna (101). Predetermined changes of phase and amplitude are applied to a second part S2 of the first signal S to produce a second electrical signal S4 which is coherent with the first part S1 of the first signal S. Microwave radiation is detected at a plurality of locations by means of a second antenna (107) to generate a third electrical signal S5 at each location. The second S4 and third S5 electrical signals are combined to produce a fourth electrical signal.

Claims

1. A microwave holographic measuring method comprising:

providing a first electrical signal of at least one microwave frequency;

directing a first part of said first signal to a first antenna;

applying predetermined changes of phase and amplitude to a second part of said first signal to produce a second electrical signal, wherein said second part is coherent with said first part;

detecting microwave radiation at a plurality of locations using a second antenna to generate a respective third electrical signal at each said location; and

combining said second and third signals to produce a fourth electrical signal.

2. A method according to claim 1, wherein the predetermined changes of phase and amplitude are chosen to reproduce a predetermined microwave signal at each said location.

3. A method according to claim 1, wherein the method is a method of measuring radiation characteristics of the first antenna.

4. A method according to claim 3, further comprising comparing values of said fourth electrical signal with corresponding values of the fourth electrical signal for an antenna of known characteristics.

5. A method according to claim 1, wherein the method is a method of forming a microwave image of an object, and further comprises illuminating the object with said first part.

6. A method according to claim 5, further comprising combining said fourth signal with a signal representing predetermined microwave radiation to generate holographic image data for each said location.

7. A method according to claim 5, further comprising applying predetermined changes of phase and amplitude to said fourth electrical signal to produce a fifth electrical signal, wherein said fifth electrical signal represents a microwave image of the object.

8. A method according to claim 5, further comprising processing said fourth electrical signal to generate data representing an image of the object at locations other than said plurality of locations.

9. A method according to claim 8, wherein the method is a method of detecting buried objects.

10. A microwave holographic measuring apparatus comprising:

at least one signal generator device for generating a first electrical signal of at least one microwave frequency;

at least one coupler device for directing a first part of said first signal to an antenna and providing a second part of said first signal, wherein said second part is coherent with said first part;

at least one phase/amplitude adjusting device for applying predetermined changes of phase and amplitude to said second part to produce a second electrical signal;

at least one first antenna for detecting microwave radiation at a plurality of locations to generate a respective third electrical signal at each said location; and

at least one combining device for combining said second and third signals to produce a fourth electrical signal.

11. An apparatus according to claim 10, further comprising at least one second antenna for receiving said first part of said first signal and illuminating an object.

12. An apparatus according to claim 10, further comprising at least one detector device for detecting said fourth signals.

13. An apparatus according to claim 10, further comprising at least one position adjusting device for adjusting the position of the or each said second antenna.

14. An apparatus according to claim 10, further comprising at least one controller device for controlling each said phase/amplitude adjusting device.