A low frequency animal radio frequency identification (RFID) system following the ISO Standard 11785, comprising: a transmit and receive antenna (400, 420, 500, 520, 600); an RFID reader circuit configured to drive the antenna (400, 420, 500, 520, 600) with an interrogation signal (414, 515); wherein the RFID reader circuit and the antenna (400, 420, 500, 520, 600) are configured to detect data modulated onto the interrogation signal (414, 515) by a passive RFID transponder of the full-duplex FDX-B type; the RFID system characterized by: the transmit and receive antenna (400, 420, 500, 520, 600) includes a plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) and at least two of the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) generate magnetic fields (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) having opposite polarity when driven by the interrogation signal (414, 515); the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) are physically arranged so that, when driven by the interrogation signal (414, 515), the magnetic field (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) proximal to each loop (401, 402, 501, 502, 503, 601, 602, 603) activates any passive RFID transponders (413, 514, 608, 609) present within a first distance from the antenna; wherein the physical arrangement of the plurality of loops causes the magnetic fields generated by the loops, when driven by the interrogation signal, to merge together and collectively cancel beyond the first distance from the antenna, and wherein the physical arrangement of the plurality of loops causes an electromagnetic signal resulting from the vibration of the metal structures at acoustic frequencies and inducing an amplitude modulation upon the interrogation signal to induce no net signal current in the antenna such that the electromagnetic signal is canceled or significantly attenuated when the metal structures are positioned at or beyond the first distance from the antenna. a transmit and receive antenna (400, 420, 500, 520, 600); an RFID reader circuit configured to drive the antenna (400, 420, 500, 520, 600) with an interrogation signal (414, 515); wherein the RFID reader circuit and the antenna (400, 420, 500, 520, 600) are configured to detect data modulated onto the interrogation signal (414, 515) by a passive RFID transponder of the full-duplex FDX-B type; the RFID system characterized by: the transmit and receive antenna (400, 420, 500, 520, 600) includes a plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) and at least two of the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) generate magnetic fields (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) having opposite polarity when driven by the interrogation signal (414, 515); the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) are physically arranged so that, when driven by the interrogation signal (414, 515), the magnetic field (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) proximal to each loop (401, 402, 501, 502, 503, 601, 602, 603) activates any passive RFID transponders (413, 514, 608, 609) present within a first distance from the antenna; wherein the physical arrangement of the plurality of loops causes the magnetic fields generated by the loops, when driven by the interrogation signal, to merge together and collectively cancel beyond the first distance from the antenna, and wherein the physical arrangement of the plurality of loops causes an electromagnetic signal resulting from the vibration of the metal structures at acoustic frequencies and inducing an amplitude modulation upon the interrogation signal to induce no net signal current in the antenna such that the electromagnetic signal is canceled or significantly attenuated when the metal structures are positioned at or beyond the first distance from the antenna. the transmit and receive antenna (400, 420, 500, 520, 600) includes a plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) and at least two of the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) generate magnetic fields (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) having opposite polarity when driven by the interrogation signal (414, 515); the plurality of loops (401, 402, 501, 502, 503, 601, 602, 603) are physically arranged so that, when driven by the interrogation signal (414, 515), the magnetic field (406, 407, 408, 409, 421, 422, 507, 508, 509, 510, 521, 522, 523) proximal to each loop (401, 402, 501, 502, 503, 601, 602, 603) activates any passive RFID transponders (413, 514, 608, 609) present within a first distance from the antenna; wherein the physical arrangement of the plurality of loops causes the magnetic fields generated by the loops, when driven by the interrogation signal, to merge together and collectively cancel beyond the first distance from the antenna, and wherein the physical arrangement of the plurality of loops causes an electromagnetic signal resulting from the vibration of the metal structures at acoustic frequencies and inducing an amplitude modulation upon the interrogation signal to induce no net signal current in the antenna such that the electromagnetic signal is canceled or significantly attenuated when the metal structures are positioned at or beyond the first distance from the antenna.