Method and apparatus for detecting microwave fields

Claim 2

A detector for displaying the intensity distribution of a microwave field comprising: a continuous layer of resistive material of constant thickness having a resistivity between 10 and 120 times that of copper, adapted to receive said microwave field for providing induced internal electrical currents in response thereto said layer having a resistivity of 100-500 ohms/square thereby establishing a temperature distribution on said layer corresponding to said microwave distribution; and liquid crystal temperature sensitive film means, disposed contiguous to said layers of resistive material for imposition of said temperature distribution thereon through thermal transfer between said film means and said layer, for providing a visible display representative of said temperature distribution, said film means being adapted for changing said visible display in accord with changes in said temperature distribution.

Claim 3

The detector of claim 1 wherein said temperature sensitive film means comprises cholesteric liquid crystalline phase material.

Claim 4

The detector of claim 1 further including membrane means for supporting said layer and said film means having a predetermined low microwave absorption coefficient.

Claim 5

The detector of claim 1 wherein said resistive material has a resistivity between 50 and 80 times that of copper.

Claim 6

The detector of claim 1 wherein said resistive material is nichrome.

Claim 7

The detector of claim 1 wherein said layer has a resistivity of approximately 188.5 ohms per square.

Claim 8

The detector of claim 1 further including a calibration circuit comprising: a variable source of heating current adapted to be connected to said resistive layer for flow of said heating current therethrough; and means for measuring said heating currents whereby the effects of said heating currents on said visible display may be quantitatively compared with the effects of said microwave field.

Claim 9

A detector for providing a substantially real time display of the intensity distribution of a microwave field comprising: a continuous layer of nichrome of constant thickness positioned to receive said microwave field for providing induced internal electrical currents in response to said microwave field intensity distribution thereby establishing a temperature distribution on said layer corresponding to said intensity distribution, said layer having a resistivity of 377 ohms per square and a prEdetermined thickness for permeation of said induced currents through the entire of said layer; a cholesteric liquid crystalline film, contiguous said layer for imposition of said temperature distribution thereon through thermal conduction between said film and said layer, for providing a visible display representative of said temperature distribution; and membrane means for supporting said layer and said film having a predetermined low microwave absorption coefficient.

Claim 10

A detector for providing a substantially real time display of the intensity distribution of a microwave field comprising: a continuous layer of nichrome of constant thickness positioned to receive said microwave field for providing induced internal electrical currents in response to said microwave field intensity distribution thereby establishing a temperature distribution on said layer corresponding to said intensity distribution, said layer having a resistivity of 377 ohms per square and a prEdetermined thickness for permeation of said induced currents through the entire of said layer; a cholesteric liquid crystalline film, contiguous said layer for imposition of said temperature distribution thereon through thermal conduction between said film and said layer, for providing a visible display representative of said temperature distribution; and membrane means for supporting said layer and said film having a predetermined low microwave absorption coefficient.

Claim 11

The detector of claim 8 further including a calibration circuit comprising: a variable source of heating current adapted to be connected across opposite ends of said resistive layer; and means for measuring said heating currents whereby the effects of said heating currents on said visible display may be quantitatively compared with the effects of said microwave field.

Claim 12

A detector for displaying the intensity distribution of a field of microwave energy having a predetermined wavelength comprising: a resistive layer of constant thickness adapted to receive said microwave energy for providing induced internal electrical currents in response thereto thereby establishing a temperature distribution on said layer corresponding to said microwave intensity distribution; temperature sensitive liquid crystal film means, disposed contiguous said resistive layer for imposition of said temperature distribution thereon through thermal transfer between said film means and said layer, for providing a visible display representative of said temperature distribution, said film means being adapted for changing said visible display in accord with changes in said temperature distribution; and conducting plane means disposed one-quarter of said wavelength from said resistive layer for receiving microwave energy transmitted through said layer and for reflecting said energy to said layer thereby providing substantially complete absorption of said reflected microwave energy in said layer.

Claim 13

A detector for displaying the intensity distribution of a field of microwave energy having a predetermined wavelength comprising: a resistive layer of constant thickness adapted to receive said microwave energy for providing induced internal electrical currents in response thereto thereby establishing a temperature distribution on said layer corresponding to said microwave intensity distribution; temperature sensitive liquid crystal film means, disposed contiguous said resistive layer for imposition of said temperature distribution thereon through thermal transfer between said film means and said layer, for providing a visible display representative of said temperature distribution, said film means being adapted for changing said visible display in accord with changes in said temperature distribution; and conducting plane means disposed one-quarter of said wavelength from said resistive layer for receiving microwave energy transmitted through said layer and for reflecting said energy to said layer thereby providing substantially complete absorption of said reflected microwave energy in said layer.

Claim 14

The detector of claim 10 wherein said layer consists essentially of a material having a resistivity between 50 and 80 times that of copper.

Claim 15

The detector of claim 10 further including a calibration circuit comprising: a variable source of heating current adapted to be connected to said resistive layer for flow of said heating current therethrough; and means for measuring said heating currents whereby the effects of said heating currents on said visible display may be quantitatively compared with the effects of said microwave field.

Claim 16

The detector of claim 10 wherein said temperature sensitive film means comprises cholesteric liquid crystalline phase material.

Claim 17

The detector of claim 10 wherein said layer has a resistivity of approximately 377 ohms per square.