Nova Patents
US3683389A

Omnidirectional loop antenna array

Abstract

An antenna array for use with a system for receiving signals from a radio capsule disposed within a patient's gastrointestinal tract. The array of antennas comprises three mutually perpendicular loop antennas, two of which are ferrite-core loop antennas disposed near the center of the array, the third being a loop antenna surrounding the two ferrite-core antennas. The antenna array includes means for matching the impedance of the loop antennas to transmission lines to which they are to be connected.

US3683389A, drawing sheet 1
Sheet 1 of 2

Term

Term ended

Expired 8 August 1989, 37.1 years ago.

  1. Priority and filed
  2. Granted
  3. Expired
  4. Today

15 claims: 15 independent, 0 dependent

  1. 1
    I claim:1. In a system for receiving signals from a radio capsule, wherein any one of an omnidirectional array of antennas suitable for disposition adjacent to a patient is connected by switching means to a radio receiver, said array of antennas being characterized in that it comprises: a first ferrite-core loop antenna, a second ferrite-core loop antenna, the axis thereof being perpendicular to that of said first loop antenna, and a third loop antenna surrounding said first and second loop antennas, the axes of said first and second loop antennas being perpendicular to that of said third loop antenna so that at least one of said antennas can receive a usable signal from said radio capsule, regardless of the orientation of said radio capsule.
  2. 2
    A system in accordance with claim 1 wherein said array of antennas further comprises first, second and third pairs of terminals, first means for matching the impedance of said first antenna to said first pair of terminals, second means for matching the impedance of said second antenna to said second pair of terminals and third means for matching the impedance of said third antenna to said third pair of terminals.
  3. 3
    A system in accordance with claim 2 wherein said first loop antenna comprises a first multi-tum loop, said first means comprising a first one-turn loop wound adjacent to said first multi-tum loop, the ends of said first one-turn loop being connected to said first pair of terminals, said second loop antenna comprises a second multi-tum loop, said second means comprising a second one-turn loop wound adjacent to said second multi-tum loop, the ends of said second one-turn loop being connected to said second pair of terminals, and said third loop antenna comprises a third multi-tum loop, said third means comprising a third one-turn loop wound adjacent to said third multi-tum loop, the ends of said third one-turn loop being connected to said third pair of terminals.
  4. 4
    A system in accordance with claim 3 further comprising first, second and third variable tuning capacitors in series with said first, second and third multi-turn loops, respectively.
  5. 5
    A system in accordance with claim 4 wherein said first and second ferrite-core loop antennas comprise first and second elongated crossed ferrite rods, said first and second single turn loops and said first and second multi-tum loops being disposed on said ferrite rods.
  6. 6
    A system in accordance with claim 5 wherein said array of antennas is further characterized in that said first and second single-turn loops and said first and second multi-tum loops are disposed at the intersection of said first and second ferrite rods, both of said rods disposed within each of said loops.
  7. 7
    A system in accordance with claim 2 wherein said first, second and third means comprise electrical connections from said first, second and third pairs of terminals to taps on said first, second and third loop antennas, respectively.
  8. 8
    An antenna array comprising 3,683,389 a pair of elongated crossed ferrite rods, a first multi-tum loop antenna wound around said rods at the intersection thereof, a second multi-tum loop antenna wound around said rods at the intersection thereof, the axis of said second loop antenna being perpendicular to the axis of said first loop antenna, a third multi-tum loop antenna surrounding said first and second loop antennas, the axes of said first and second loop antennas being perpendicular to that of said third loop antenna, first, second and third variable timing capacitors in series with said first, second and third loop antennas, respectively, first, second and third pairs of terminals, first means for matching the impedance of said first antenna to said first pair of terminals, second means for matching the impedance of said second antenna to said second pair of terminals, and third means for matching the impedance of said third antenna to said third pair of terminals.
  9. 9
    An antenna array in accordance with claim 8 wherein said first means comprises a first one-tum loop wound adjacent to said first multi-tum loop, the ends of said first one-tum loop being connected to said first pair of terminals, said second means comprises a second one-tum loop wound adjacent to said second multi-tum loop, the ends of said second one-tum loop being connected to said second pair of terminals, and said third means comprises a third one-tum loop wound adjacent to said third multi-tum loop, the ends of said third one-tum loop being connected to said third pair of terminals.
  10. 10
    An antenna array in accordance with claim 8 wherein said first, second and third means comprise electrical connections from said first, second and third pairs of terminals to taps on said first, second and third loop antennas, respectively.
  11. 11
    An antenna array in accordance with claim 8 wherein said first means comprises a fourth loop wound adjacent to said first multi-tum loop, the ends of said fourth loop being connected to said first pair of terminals, said second means comprises a fifth loop 5 wound adjacent to said second multi-tum loop, the ends of said fifth loop being connected to said second pair of terminals, and said third means comprises a sixth loop wound adjacent to said third multi-tum loop, the ends of said sixth loop being connected to said third 10 pair of terminals, said fourth, fifth and sixth loops comprising fewer turns than said first, second and third loops, respectively.
  12. 12
    An antenna array in accordance with claim 11 wherein said first, second and third loop antennas each 15 consists of a first number of loops and said third, fourth and fifth loops each consists of a second number of loops.
  13. 13
    A system in accordance with claim 1 wherein said first and second ferrite core loop antennas com20 prise first and second elongated crossed ferrite rods and first and second multi-tum loops disposed on both of said rods at the intersection thereof.
  14. 14
    A system in accordance with claim 13 wherein said third loop antenna is disposed in a plane which is 25 parallel to the axes of said first and second ferrite rods.
  15. 15
    An antenna array comprising a flat substrate, a pair of elongated crossed ferrite rods disposed on said substrate, 3Q a first multi-tum loop antenna wound around said rods at the intersection thereof, a second multi-tum loop antenna wound around said rods at the intersection thereof, the axis of said second loop antenna being perpendicular to the 35 axis of said first loop antenna, and a third multi-tum loop antenna disposed on said substrate and surrounding said first and second loop antennas, the axes of said first and second loop antennas being perpendicular to that of said third 40 loop antenna.
Independent claims15