Body worn antenna

A wearable antenna for communicating between an external transceiver and a capsule inside the gastrointestinal tract of a user, including a printed circuit board for forming a conducting pattern on a first face and on a second face of the printed circuit board; a first conducting pattern on the first face of the printed circuit board, including: a) an almost completely split conducting elongated bar across a center of the printed circuit board; b) an identical main conducting transmission area on each side of the almost completely split elongated bar; c) a thin conducting line respectively connecting between each side of the almost completely split elongated bar and the transmission area; a second conducting pattern on the second face of the printed circuit board including a U shaped conductor; wherein the U shaped conductor is positioned to serve as a balun for the conducting pattern on the first face.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to an antenna that is worn on a person's body to communicate with a capsule that was swallowed by the person and is traveling through the gastrointestinal tract.

BACKGROUND OF THE DISCLOSURE

One method for examining the gastrointestinal tract for the existence of polyps and other clinically relevant features that may provide an indication regarding the potential of cancer is performed by swallowing an imaging capsule that travels through the gastrointestinal tract and views the patient's situation from within. In a typical case the trip can take between 24-48 hours, after which the imaging capsule exits in the patient's feces. Typically the patient swallows a contrast agent to enhance the imaging ability of the imaging capsule. Then the patient swallows the imaging capsule to examine the gastrointestinal tract while flowing through the contrast agent. The imaging capsule typically includes a radiation source, for example including a radioisotope that emits X-rays and/or Gamma rays. The radiation typically may be collimated to allow it to be controllably directed toward a specific area during the imaging process. In an exemplary case the imaging capsule is designed to measure X-Ray fluorescence and/or Compton back-scattering and transmit the measurements (e.g. count rate, particle energy) to an external analysis device, for example an external transceiver worn by the patient and/or a computer or other dedicated instruments.

U.S. Pat. No. 7,787,926 dated Aug. 31, 2010 and U.S. Pat. No. 9,037,219 dated May 19, 2015 both by the current applicant, the disclosures of which are incorporated herein by reference, describe details related to the manufacture and use of such an imaging capsule.

It is desirable to minimize the amount of power required by the imaging capsule to successfully perform its trip through the gastrointestinal tract so that the size of a required power source can be reduced. Therefore it is desirable to optimize communications to reduce the amount of power required to communicate with the external transceiver.

SUMMARY OF THE DISCLOSURE

An aspect of an embodiment of the disclosure, relates to a wearable antenna that can be attached to the lower back of a user or placed at other locations on the user's body near the gastrointestinal tract of the user, for example near the colon and small intestine. The wearable antenna is designed to provide an electromagnetic radiation pattern that optimally covers the path of a capsule traversing the gastrointestinal tract. The wearable antenna is made from a two faced printed circuit board with a printed conducting pattern on both faces of the printed circuit board. On a first face there is printed an almost symmetrical pattern having a split elongated bar down the center of the printed circuit board and an identical main transmission area on either side of the split elongated bar to form a dipole transmission antenna. On each side of the split elongated bar a thin conducting line connects between a side of the split elongated bar and the main radiation area. On the second face there is printed an elongated bar approximately down the center of the printed circuit board to serve as a balun for the antenna. Optionally, the elongated bar on the second face is shifted right or left from the center to balance the transmission signal.

In an exemplary embodiment of the disclosure, the pattern of the conducting areas on the face of the antenna are designed to optimally serve as a transceiver antenna using an ISM band frequency (e.g. 433 Mhz) and taking into account the influence of the user's body being attached to the antenna.

There is thus provided according to an exemplary embodiment of the disclosure, a wearable antenna for communicating between an external transceiver and a capsule inside the gastrointestinal tract of a user, comprising:

a printed circuit board for forming a conducting pattern on a first face and on a second face of the printed circuit board;

a first conducting pattern on the first face of the printed circuit board, comprising:a) an almost completely split conducting elongated bar across a center of the printed circuit board forming a void between each side of the almost completely split elongated bar;b) an identical main conducting transmission area on each side of the almost completely split elongated bar;c) a thin conducting line respectively connecting between each side of the almost completely split elongated bar and the transmission area;

a second conducting pattern on the second face of the printed circuit board comprising a U shaped conductor having an elongated conducting area and an elongated conducting line; wherein the U shaped conductor is positioned to serve as a balun for the conducting pattern on the first face; and

wherein the size of the printed circuit board is selected to be attachable to the lower back of the user and to transmit a signal having an ISM band frequency.

In an exemplary embodiment of the disclosure, the U shaped conductor on the second face of the printed circuit board is positioned with an offset relative to the center of the printed circuit board to balance the signal transmitted by the wearable antenna. Optionally, the U shaped conductor on the second face of the printed circuit board is shorted with the almost completely split conducting elongated bar on the first face of the printed circuit board. In an exemplary embodiment of the disclosure, the U shaped conductor is shorted with the almost completely split conducting elongated bar by via holes through the printed circuit board. Alternatively, the U shaped conductor is shorted with the almost completely split conducting elongated bar by an electrical connection along the external width of the printed circuit board. In an exemplary embodiment of the disclosure, the antenna is connected with a cable to an external transceiver located near the waist of the user. Optionally, the almost completely split conducting bar is larger than the main conducting transmission areas together. In an exemplary embodiment of the disclosure, the main conducting transmission areas together are larger than the almost completely split conducting bar. Optionally, one side of the almost completely split elongated bar includes an elongated line extending inward next to the void. In an exemplary embodiment of the disclosure, the elongated line has an identical or similar thickness as the elongated conducting line of the U shaped conductor.

There is further provided according to an exemplary embodiment of the disclosure, a method of communicating between an external transceiver and a capsule inside the gastrointestinal tract of a user, comprising:

attaching a wearable antenna to the body of the user wherein the wearable antenna includes a printed circuit board having a conducting pattern on a first face and on a second face of the printed circuit board;

preparing the printed circuit board by printing a first conducting pattern on the first face of the printed circuit board, comprising:a) an almost completely split conducting elongated bar across a center of the printed circuit board forming a void between each side of the almost completely split elongated bar;b) an identical main conducting transmission area on each side of the almost completely split elongated bar;c) a thin conducting line respectively connecting between each side of the almost completely split elongated bar and the transmission area;

preparing the printed circuit board by further printing a second conducting pattern on the second face of the printed circuit board comprising a U shaped conductor having an elongated conducting area and an elongated conducting line; wherein the U shaped conductor is positioned to serve as a balun for the conducting pattern on the first face; and

wherein the size of the printed circuit board is selected to be attachable to the lower back of the user and to transmit a signal having an ISM band frequency.

In an exemplary embodiment of the disclosure, the U shaped conductor on the second face of the printed circuit board is positioned with an offset relative to the center of the printed circuit board to balance the signal transmitted by the wearable antenna. Optionally, the U shaped conductor on the second face of the printed circuit board is shorted with the almost completely split conducting elongated bar on the first face of the printed circuit board. In an exemplary embodiment of the disclosure, the U shaped conductor is shorted with the almost completely split conducting elongated bar by via holes through the printed circuit board. Alternatively, the U shaped conductor is shorted with the almost completely split conducting elongated bar by an electrical connection along the external width of the printed circuit board. In an exemplary embodiment of the disclosure, the antenna is connected with a cable to an external transceiver located near the waist of the user. Optionally, the almost completely split conducting bar is larger than the main conducting transmission areas together. In an exemplary embodiment of the disclosure, the main conducting transmission areas together are larger than the almost completely split conducting bar. Optionally, one side of the almost completely split elongated bar includes an elongated line extending inward next to the void. In an exemplary embodiment of the disclosure, the elongated line has an identical or similar thickness as the elongated conducting line of the U shaped conductor.

DETAILED DESCRIPTION

FIG. 1is a schematic illustration of a wearable antenna100deployed on a user, according to an exemplary embodiment of the disclosure. In an exemplary embodiment of the disclosure, the user swallows a capsule110to examine the gastrointestinal tract190and especially the colon195. Optionally, the capsule110includes a power source103and transceiver104for communicating with an external transceiver105that may be deployed around the user's waist, for example on a belt107. In an exemplary embodiment of the disclosure, the wearable antenna100is attached to the user's body, for example adhesively attached to the user's lower back or lower part of the stomach to transmit and receive signals120communicated between the capsule110(e.g. when located in the colon195or small intestine) and the external transceiver105. Optionally, the wearable antenna100may be taped to the body of the user, for example with a two sided tape or with a piece of tape170that is larger than the wearable antenna100. In an exemplary embodiment of the disclosure, the wearable antenna100is connected to the external transceiver105with a cable130(e.g. coaxial cable) for providing a signal120to the wearable antenna100and/or receiving a signal120. In some embodiments of the disclosure, external transceiver105may communicate with a computer180to assist in analyzing information received from the capsule110. Optionally, the capsule110may record images, deliver medication and/or perform other actions as known in the art.

FIG. 2is a schematic illustration of wearable antenna100, according to an exemplary embodiment of the disclosure. In an exemplary embodiment of the disclosure, the wearable antenna100is designed to optimally communicate with the capsule110. Optionally, the wearable antenna100is essentially shaped as a circle with a radius of about 20-40 mm. In an exemplary embodiment of the disclosure, the wearable antenna100is formed by printing a conducting layer on a first face and a second face of an electrically isolated printed circuit board (PCB)140. Optionally, the printed circuit board140may be rigid or alternatively it may be elastic so that it can bend with the curvature of the user's body when deployed on the user's body. In an exemplary embodiment of the disclosure, the printed circuit board140is made from a flame retardant (FR) material such as FR-4, which is made from a glass reinforced epoxy laminate sheet. Optionally, the width of the circuit board is between 0.1 mm to 1.0 mm, for example 0.254 mm (10 milli-inches).

FIG. 3Ais a schematic illustration of a conducting layer300printed on a first face of the wearable antenna100, andFIG. 3Bis a schematic illustration of a conducting layer350printed on a second face of the wearable antenna100, according to an exemplary embodiment of the disclosure. In an exemplary embodiment of the disclosure, the conducting layer300on the first face of the printed circuit board140is designed as a planar dipole antenna having an almost completely split central elongated bar area310with each side of the elongated bar area310connected by a thin conducting line330to one of two main transmission areas320,325. In an exemplary embodiment of the disclosure, the split in the middle of elongated bar area310forms a void317serving as an induction split between both sides of the elongated bar area310. Optionally, the transmission area (320,325) are positioned symmetrically on opposite sides of the elongated bar area310and the transmission areas (320,325) are shaped as solid conducting shaped areas of similar shape and size to form a dipole signal based on two identical slightly phase shifted radiating electromagnetic signals. In some embodiments of the disclosure, the solid conducting shaped areas are rectangular. Alternatively, the transmission areas may have other identical shapes, such as triangles, ellipses, circles, trapezoids or squares. In some embodiments of the disclosure, the main transmission areas (320,325) together are larger than the elongate bar area310to enhance the dipole transmission. Alternatively, the elongated bar area310is larger than the area of the main transmission areas to provide a stronger offset for the dipole radiation signal. In some embodiments of the disclosure, one side of the elongated bar area310includes an elongated line315extending inward from the elongated bar area310next to void317. Optionally, the elongated line315is thinner than the elongated bar area310.

In an exemplary embodiment of the disclosure, the conducting layer350on the second face of the printed circuit board140includes a U shaped conducting area to serve as a balun for wearable antenna100. In an exemplary embodiment of the disclosure, the U shaped conducting area includes an elongated conducting area370and an elongated conducting line380that control the inductive coupling with conducting layer300and it various parts (e.g.310,315,320,325,330, and340).

Optionally, the elongated conducting area370is thicker than the elongated conducting line380. In an exemplary embodiment of the disclosure, the elongated conducting area370and/or the elongated conducting line380are slightly shifted off from the center to the sides by a predetermined amount to control the influence of the balun in balancing the radiation signals of the wearable antenna100. Optionally, the elongated conducting area370and the elongated conducting line380are isolated from the conducting layer300printed on a first face of the wearable antenna100. Alternatively, the elongated conducting area370and the elongated conducting line380are electrically connected to the printed layer on the first face by a base area360on the second face that is connected to a base area340on the first face, for example the two faces being connected along the external width of the printed circuit board140or through via holes345between base area340and base area360. In some embodiments of the disclosure, a connection block390serves as a mediator between elongated conducting line380and base area360. Optionally, the elongated conducting line380may be electrically disconnected from base area360or may be electrically connected. In some embodiments of the disclosure, connection block390may include a capacitor or inductor to control the connection with base360. In some embodiments of the disclosure, cable130is connected from transceiver105to elongated conducting area370and elongated conducting line380, for example cable130may be a coax cable with the core connected to elongated conducting line380and the ground connected to elongated conducting area370. Optionally the line may include capacitors135or inductors to control the signals handled by the wearable antenna100.

In some embodiments of the disclosure, the thickness of elongated conducting line380is similar or identical to the thickness of elongated line315

In an exemplary embodiment of the disclosure, the antenna is configured to communicate with the capsule110using an ISM radio band signal to fit international regulations, for example a 433 Mhz signal and having a 10 Mhz bandwidth. Optionally, wearable antenna100is designed to have a single ended (unbalanced) impedance, for example of about 50 Ohm when positioned in the proximity of the body of a user (e.g. taking into account the dielectric properties of the body of the user).

In an exemplary embodiment of the disclosure, the design of wearable antenna100is optimally tuned empirically so that it generates an almost uniform omnidirectional 3D radiation pattern when deployed near the body of the user. Optionally, wearable antenna100also provides an enhanced power gain in contrast to other antennas of similar size when transmitting with ISM frequencies near a user's body.

FIG. 4is a schematic graph400of a 3 dimensional radiation pattern400using the wearable antenna, andFIG. 5is a schematic graph500of power gain versus angle using the wearable antenna, according to an exemplary embodiment of the disclosure.

As shown by graph400and graph500the signal provided by wearable antenna100spreads out evenly to cover the surroundings of the wearable antenna, thus providing a good connection with capsule110especially after leaving the stomach and reaching the small intestine and colon.

It should be appreciated that the above described methods and apparatus may be varied in many ways, including omitting or adding steps, changing the order of steps and the type of devices used. It should be appreciated that different features may be combined in different ways. In particular, not all the features shown above in a particular embodiment are necessary in every embodiment of the disclosure. Further combinations of the above features are also considered to be within the scope of some embodiments of the disclosure.