Devices, methods and systems using load-pulled electronic monitoring

• US 5,966,017 A
• Filed: 05/05/1998
• Issued: 10/12/1999
• Est. Priority Date: 07/26/1993
• Status: Expired due to Term

• Current Assignee: Phase Dynamics, Inc.
• Original Assignee: Phase Dynamics, Inc.
• Inventors: Scott, Bentley N., Shortes, Samuel R.
• Primary Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US09/072,822
• Time in Patent Office: 525 Days
• Field of Search: 324/633, 324/637, 324/639, 324/640, 324/642, 324/643, 324/647, 324/682, 324/690, 324/754, 333/34, 333/246, 333/263
• US Class Current: 324/639
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01N 22/04 Investigating moisture content
• CPC Class Codes: G01R 1/06772 High frequency probes
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24

Abstract

Systems, methods, and probe devices for electronic monitoring and characterization using single-ended coupling of a load-pulled oscillator to a system under test.

Claims

1. A method for detecting the composition and microstructure of materials, comprising the steps of:

providing an oscillator which is connected to be pulled by the varying susceptance seen at a load connection thereto;

connecting said load connection to the material under test through a single-ended probe which includes a substantially planar metal film structure which is patterned to provide a transmission line extending from said load connection, and which also includes a selective absorption material, which is selective to preferentially absorb a predetermined target species, and which is mechanically affixed to said probe to provide efficient electromagnetic coupling to said transmission line; and

observing changes in the frequency of said oscillator.

2. A system for detecting the composition and microstructure of materials, comprising:

an oscillator, which includes a gain element capable of providing substantial gain at frequencies greater than 100 MHz, and a feedback path, coupling an output of said gain element to an input thereof;

an electromagnetic propagation structure which is RF-coupled to said oscillator

and in which electromagnetic wave propagation is electrically loaded by a portion of the material to be characterized,

said propagation structure being mechanically connected to a selective absorption material, which is selective to preferentially absorb a predetermined target species, and electrically configured to provide efficient electromagnetic coupling to said propagation structure, and also to a heater integrated with said propagation structure in a common package; and

circuitry connected to monitor the frequency of said oscillator to ascertain changes in the composition or microstructure of the material, and to activate said heater selectively when said absorption material has become loaded.

3. The system of claim 2, wherein said propagation structure is nonresonant at all frequencies of operation of said oscillator.

4. A single-ended RF probe, for providing a bidirectional RF interface over a range including at least one predetermined operating frequency, to detect the presence of at least one target species in a quantity of material, comprising:

an external RF connection mechanically connected to a support structure;

a conductive structure which is electrically connected to said external connection and mechanically supported by said support structure, and which provides a transmission line extending from said external connection; and

a resistive heater which is mechanically supported by said support structure, and connected to receive a drive current; and

a selective absorption material, which is selective to preferentially absorb a predetermined target species, and which is mechanically connected to said support structure in a relation which provides efficient electromagnetic coupling to said transmission line.

5. The probe of claim 4, wherein said transmission line is nonresonant over at least a predetermined range of operating frequencies.