An RFID tag assembly comprising: an RFID tag having a mounting substrate with an exposed first planar surface (17, 82) and an opposing second planar surface (15, 84) and a length (L MS) and a width(H MS), said RFID tag having an RFID semiconductor chip having a predetermined operating frequency with an antenna interface mounted on the second planar surface (15, 84) of the mounting substrate, a conductor electrically coupled to the antenna interface of the RFID semiconductor chip, and a planar antenna electrically coupled to the conductor positioned substantially planar with the RFID semiconductor chip and conductor; and a spacer composed of a foam material, said spacer having a first side that is attached to the second planar surface (15, 84) of the mounting substrate and overlying the RFID chip, conductor and antenna mounted thereon, wherein at least one of the exposed first planar surface (17, 82) of the mounting substrate and a second side of the spacer opposite the first side attached to the second planar surface (15, 84) of the mounting substrate is adapted for selective attachment to a surface (87, 89) of a carrier, the carrier having a carrier thickness defined between a front planar surface and an opposing back planar surface, and characterised in that the RFID tag assembly is adapted for use in tracking or timing of a progress of a user on which the assembly is associated during a timed sporting event; the mounting substrate is composed of a polyester film; the planar antenna is a two-sided planar antenna; the spacer is composed of a foam material that is non-conducting and non-absorbing of a substantial amount of energy at the predetermined operating frequency; and wherein the spacer has a thickness and has a length and a width each of which is respectively greater than the length (L SP) and width (H SP) of the mounting substrate, the spacer providing a sealing of the RFID semiconductor chip, conductor and antenna to the second planar surface of the mounting substrate and overlying the RFID chip, conductor and antenna mounted thereon from external foreign substances and moisture, the spacer having a thickness for positioning the RFID tag at a spaced apart distance from a surface of the body of the user during operation of the RFID tag, the spaced apart distance being equal to or greater than a minimum spaced apart distance (d MIN) being at least one of the sum of the thickness of the spacer and the thickness of the carrier when the carrier is positioned between the spacer and the user and the thickness of only the spacer when the carrier is positioned on the first surface (17, 82) of the mounting substrate, the minimum spaced apart distance (d MIN) being greater than or equal to about 1/4 of a wavelength of the predetermined operating frequency. an RFID tag having a mounting substrate with an exposed first planar surface (17, 82) and an opposing second planar surface (15, 84) and a length (L MS) and a width(H MS), said RFID tag having an RFID semiconductor chip having a predetermined operating frequency with an antenna interface mounted on the second planar surface (15, 84) of the mounting substrate, a conductor electrically coupled to the antenna interface of the RFID semiconductor chip, and a planar antenna electrically coupled to the conductor positioned substantially planar with the RFID semiconductor chip and conductor; and a spacer composed of a foam material, said spacer having a first side that is attached to the second planar surface (15, 84) of the mounting substrate and overlying the RFID chip, conductor and antenna mounted thereon, wherein at least one of the exposed first planar surface (17, 82) of the mounting substrate and a second side of the spacer opposite the first side attached to the second planar surface (15, 84) of the mounting substrate is adapted for selective attachment to a surface (87, 89) of a carrier, the carrier having a carrier thickness defined between a front planar surface and an opposing back planar surface, and characterised in that the RFID tag assembly is adapted for use in tracking or timing of a progress of a user on which the assembly is associated during a timed sporting event; the mounting substrate is composed of a polyester film; the planar antenna is a two-sided planar antenna; the spacer is composed of a foam material that is non-conducting and non-absorbing of a substantial amount of energy at the predetermined operating frequency; and wherein the spacer has a thickness and has a length and a width each of which is respectively greater than the length (L SP) and width (H SP) of the mounting substrate, the spacer providing a sealing of the RFID semiconductor chip, conductor and antenna to the second planar surface of the mounting substrate and overlying the RFID chip, conductor and antenna mounted thereon from external foreign substances and moisture, the spacer having a thickness for positioning the RFID tag at a spaced apart distance from a surface of the body of the user during operation of the RFID tag, the spaced apart distance being equal to or greater than a minimum spaced apart distance (d MIN) being at least one of the sum of the thickness of the spacer and the thickness of the carrier when the carrier is positioned between the spacer and the user and the thickness of only the spacer when the carrier is positioned on the first surface (17, 82) of the mounting substrate, the minimum spaced apart distance (d MIN) being greater than or equal to about 1/4 of a wavelength of the predetermined operating frequency.