# Patent

## Title
Apparatus and method for electromagnetic wave structure modulation

## Abstract

Electromagnetic wave structure modulation apparatus comprises an encoded device that has an electromagnetic wave-transparent material having a three-dimensional volume and electromagnetic wave-opaque walls, and a plurality of electromagnetic wave-opaque projections projecting into the electromagnetic wave-transparent material. The apparatus further comprises an interrogating device that has a transceiver operable to transmit an electromagnetic wave into the electromagnetic wave-transparent material, the electromagnetic wave being modulated and reflected by the electromagnetic wave-opaque walls and projections, an antenna operable to receive the reflected electromagnetic waves, and a decoder operable to decode the received reflected electromagnetic waves.

## Background
RELATED APPLICATION
This non-provisional patent application claims the benefit of provisional patent application No. 61/610,175 filed on Mar. 13, 2012, which is incorporated by reference in its entirety.


FIELD
The present disclosure relates to an apparatus and method for electromagnetic wave structure modulation.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified block diagram of an exemplary system and method for electromagnetic wave structure modulation;
FIG. 2 is a simplified side view of an exemplary system and method for electromagnetic wave structure modulation; and
FIG. 3 is a simplified perspective view of an exemplary system and method for electromagnetic wave structure modulation.



DETAILED DESCRIPTION
Electromagnetic wave structure modulation methodology and apparatus utilizes electromagnetic wave and precisely structured surface irregularity to retrieve encoded information as the control wave pass through the reflecting teeth or teeth and reflected back to the interrogating device. Electromagnetic waves of several frequency ranges may be used: super high frequency (SHF): 3-30 GHz, 100 mm-10 mm λ, extremely high frequency (EHF): 30-300 GHz, 10 mm-1 mm λ, and terahertz or tremendously high frequency (THz or THF): 300-3,000 GHz, 1 mm-100 μm λ.
The apparatus/device includes two key components: (1) encoded device, and (2) interrogating device. The interrogating device includes an antenna, transceiver, and decoder. The encoded device is a passive device with a cavity filled or formed of an electromagnetic wave-transparent material that has three-dimensional electromagnetic wave-opaque encode structures or “teeth,” “fingers,” and other three-dimensional projections of various shapes and dimensions (length, thickness, width, and position) projecting into the cavity. The cavity also includes a final reflector, having a specific angle. The three-dimensional projections modifies the controlling wave as it enters into the cavity and reflects the modified wave back to the interrogator. The size, depth, and angles of the cavity determine the resonating frequency and phase of the carrier signal upon reflecting back to the interrogating device. The three-dimensional projections within the cavity determine the minor phase shifting, number of reflections, and/or times between reflections within the carrier signal. Both carrier signal and the encoded reflections contain the predetermined information which may be decoded by an interrogating device.
The interrogating device consists of a transceiver and decoder. The transceiver is capable to transmit frequencies within a predetermined frequency range, and to receive reflected encoded signal from the encoded device. The transceiver interrogates the encoded devices by sweeping through predetermined frequency channels and listens to the reflections from the encoded devices. As soon as a reflected signal is detected, the transceiver passes the signal to the decoder for retrieving the encoded information. The transceiver may also utilize the frequency and phase domain of the reflected carrier signals from the encoded devices to perform anti-collision within the same read field. That is, the interrogating device can read multiple encoded devices at once.
The interrogating device transmits control waves by sweeping through frequency channels within a predetermined range. When control wave reach an encoded device which is tuned at the same frequency as the control wave, the control wave enters the encoded device's cavity. As the wave entering the cavity, the teeth modulate the control wave with the encoded device's information. Upon reaching the final reflector of the cavity, the modulated wave reflected back to the interrogating device. The interrogating device receives the signal and decodes the information.
In addition to storing information in encoded devices, the encoded devices can provide temperature and pressure information due to material expansion or contraction. As the material of which the cavity and teeth are made up of expands and contracts, it slightly alters both time and phase domains of the reflected signals.
The features of the present invention which are believed to be novel are set forth below with particularity in the appended claims. However, modifications, variations, and changes to the exemplary embodiments described above will be apparent to those skilled in the art, and the system and method described herein thus encompass such modifications, variations, and changes and are not limited to the specific embodiments described herein.

## Claims

1. Electromagnetic wave structure modulation apparatus, comprising:
an interrogating device comprising:
a transceiver operable to transmit a control electromagnetic wave having a certain frequency into an encoded device, the control electromagnetic wave being modulated and reflected by the encoded device;
an antenna operable to receive the reflected and modulated electromagnetic wave; and
a decoder coupled to the antenna and configured to decode the received reflected and modulated electromagnetic wave into decoded data; and

the encoded device tuned to the control electromagnetic wave transmitted by the transceiver comprising:
a three-dimensional volume formed of a material that is transparent to the control electromagnetic wave transmitted by the transceiver;
a wall surrounding the three-dimensional volume formed of a material that is opaque to the control electromagnetic wave transmitted by the transceiver; and
a plurality of three-dimensional structures formed of a material that is opaque to the control electromagnetic wave disposed within the three-dimensional volume, each structure having specific shape, size, and position configured to modulate and reflect the control electromagnetic wave.

2. Electromagnetic wave structure modulation apparatus of claim 1, wherein the encoded device further comprises a final reflector formed of a material that is opaque to the control electromagnetic wave configured to reflect the modulated and reflected electromagnetic wave toward the interrogating device.

3. Electromagnetic wave structure modulation apparatus of claim 1, wherein the three-dimensional structures are configured to alter at least one of time and phase domains of the control electromagnetic wave.

4. Electromagnetic wave structure modulation apparatus of claim 1, wherein the three-dimensional structures comprise a plurality of three-dimensional projections projecting from the wall into the three-dimensional volume of the encoded device.

5. Electromagnetic wave structure modulation apparatus of claim 1, wherein the three-dimensional structures comprise a plurality of projections projecting from the wall into the three-dimensional volume of the encoded device, the shape and size of the projections, and the angular and linear positions of the projections in the three-dimensional volume of the encoded device being configurable to tune the encoded device.

6. An electromagnetic wave structure modulation method, comprising:
generating and directing a control electromagnetic wave of a certain frequency toward an encoded device, the encoded device comprising:
a three-dimensional volume formed of a material that is transparent to the control electromagnetic wave;
a wall surrounding the three-dimensional volume formed of a material that is opaque to the control electromagnetic wave; and
a plurality of structures formed of a material that is opaque to the control electromagnetic wave disposed within the three-dimensional volume, each structure having specific shape, size, and position within the three-dimensional volume configured to modulate and reflect the control electromagnetic wave; and
a final reflector structure formed within the three-dimensional volume of the encoded device configured to reflect the modulated and reflected electromagnetic wave;

receiving the reflected and modulated electromagnetic wave from the encoded device;
converting the received electromagnetic wave to an electrical signal; and
decoding the electrical signal.

7. A method of forming an electromagnetic wave structure modulation apparatus, comprising:
forming a three-dimensional volume of a material that is transparent to a control electromagnetic wave with a certain frequency, the three-dimensional volume having a first end and a second end;
forming a wall surrounding the three-dimensional volume of a material that is opaque to the control electromagnetic wave; and
forming a plurality of structures of a material that is opaque to the control electromagnetic wave within the three-dimensional volume, each structure having specific shape, size, and position within the three-dimensional volume configured to modulate and reflect the electromagnetic wave in a predetermined way.

8. The method of forming an electromagnetic wave structure of claim 7 further comprising forming a final reflector wall of a material that is opaque to the control electromagnetic wave disposed at the second end of the three-dimensional volume and configured to reflect the electromagnetic wave modulated and reflected by the plurality of structures toward the first end of the three-dimensional volume.