A wearable antenna for communicating between an external transceiver and a capsule inside the gastrointestinal tract of a user, comprising: a printed circuit board comprising first and second faces and first and second conductive patterns (300, 350) respectively printed on said first and second faces of said printed circuit board; and characterized by: the 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 (320, 325) 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 (320, 325); the second conducting pattern on the second face of the printed circuit board comprising a U shaped conductor (370+380) having an elongated conducting area and an elongated conducting line; wherein the U shaped conductor (370+380) 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 so that the printed circuit board is configured to be attached to the lower back of the user and to transmit a signal having an ISM band frequency. a printed circuit board comprising first and second faces and first and second conductive patterns (300, 350) respectively printed on said first and second faces of said printed circuit board; and characterized by: the 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 (320, 325) 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 (320, 325); the second conducting pattern on the second face of the printed circuit board comprising a U shaped conductor (370+380) having an elongated conducting area and an elongated conducting line; wherein the U shaped conductor (370+380) 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 so that the printed circuit board is configured to be attached to the lower back of the user and to transmit a signal having an ISM band frequency. the 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 (320, 325) 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 (320, 325); 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 (320, 325) 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 (320, 325); the second conducting pattern on the second face of the printed circuit board comprising a U shaped conductor (370+380) having an elongated conducting area and an elongated conducting line; wherein the U shaped conductor (370+380) 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 so that the printed circuit board is configured to be attached to the lower back of the user and to transmit a signal having an ISM band frequency.