Material determination by sweeping a range of frequencies

• US 9,575,014 B2
• Filed: 12/22/2014
• Issued: 02/21/2017
• Est. Priority Date: 12/22/2014
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Leek, Alan H., Szmulewicz, Damian M.
• Primary Examiner(s): Nguyen, Tung X
• Assistant Examiner(s): SHAH, NEEL D
• Application Number:
  US14/578,760
• Publication Number:
  US 20160178537A1
• Time in Patent Office: 792 Days
• Field of Search: 343/702, 324/630, 324/658, 324/637, 345173-178
• US Class Current: 1/1
• 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: G01V 3/38 Processing data, e.g. for analysis, for interpretation, for correction

Abstract

A material-discerning device is arranged to include an antenna, a proximity sensor, a band pass filter and a processor. The antenna radiates a radio-frequency signal and a material object is located in the field created by the antenna and near the proximity sensor. Change in the amplitude of the radio-frequency signal due to the presence of the material object is detected by the proximity sensor. The change in amplitude of the radio-frequency signal is stored. The frequency of the radio-frequency signal is changed and the process is repeated until a range of frequencies have been swept and stored. After the range of frequencies has been swept and stored, the processor determines the type of material of the material object using the results of the changes in amplitude of the radio-frequency signals.

Claims

1. A material-discerning device comprising:

an antenna that is arranged to radiate a radio-frequency signal;

a proximity sensor that is arranged to detect a change in amplitude of the radio-frequency signal when a material object is located near the antenna and the proximity sensor; and

a processor that compares the detected change of the radio-frequency signal with a predetermined table of materials;

wherein the processors determines which material from the predetermined table of materials the material object is composed;

wherein the processor comprises an analog-to-digital converter, the analog-to-digital converter arranged to quantify the detected change in amplitude of the radio-frequency signal using a sampling rate that is less-than-or-equal-to at least twice the frequency of a carrier wave of the transmitted radio-frequency signal.

2. A method for discerning material comprising:

radiating a radio-frequency signal using an antenna,

receiving the radio-frequency signal using a proximity sensor;

wherein a material object is located near the antenna and the proximity sensor;

detecting a change in amplitude of the radio-frequency signal on the proximity sensor;

storing the detected change of the radio-frequency signal;

repeating the above steps until a range of frequencies have been radiated; and

determining the material type of the material object in response to the detected changes in amplitude of the radio-frequency signals;

using an analog-to-digital converter to quantify detected changes in amplitude of the received radio-frequency signal using a sampling rate that is less-than-or-equal-to at least twice the frequency of a carrier wave of the transmitted radio-frequency signal.