Ferroelectric radiation detector employing frequency modulated readout

• US 8,143,578 B2
• Filed: 04/21/2009
• Issued: 03/27/2012
• Est. Priority Date: 04/21/2009
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Rod, Bernard J., Tidrow, Steven C., Crowne, Frank, Potrepka, Daniel
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US12/427,295
• Publication Number:
  US 20100264325A1
• Time in Patent Office: 1,071 Days
• Field of Search: 250330-335, 2503361-3362, 2503381-3385, 25033901-33915, 250/340, 2503411-3418
• US Class Current: 250/338.2
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence

Abstract

A detector for electromagnetic radiation such as millimeter wave and infrared employs a ring-shaped ferroelectric element having a temperature affected by an absorber for the radiation. The dielectric constant of the ferroelectric material is a strong function of the temperature near its Curie temperature. The resonant frequency of the ferroelectric element is detected by applying a swept-frequency signal to the circuit and detecting the frequency which enhances the energy of the pulse. A two-dimensional camera for the radiation employs a two-dimensional array of these ferroelectric resonant circuits and a system for rapidly interrogating their resonant frequencies on a sequential basis.

Claims

1. A method for constructing a resonant frequency electromagnetic radiation detector comprising the following steps:

providing a planer ground plane;

placing a dielectric layer on said planer ground plane;

placing a metal microstrip transmission line on said dielectric strip;

building up a mesa formed of dielectric material on said dielectric layer;

forming a ferroelectric ring on top of said mesa; and

placing a radiation absorbing layer on top of said ferroelectric ring.

2. The method of claim 1 wherein said planer ground plane is capable of supporting a resonate mode.

3. The method of claim 1 wherein said planer ground plane is formed of copper.

4. The method of claim 1 wherein said mesa is formed in a substantially cylindrical shape.

5. The method of claim 4 wherein said ferroelectric ring is formed to have a substantially similar diameter as that of said mesa.

6. The method of claim 1 wherein said ferroelectric ring is formed of Barium Strontium Titanate.

7. The method of claim 1 wherein said ferroelectric ring has a thickness in the range of 0.1-100 microns.