Passive transponder for locating avalanche victims

Claim 2

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein the antenna sheet is linearly elongate, and the cutout portion is disposed proximate a central portion of said elongate antenna sheet intermediate opposite ends thereof.

Claim 3

A passive transponder as set forth in claim 1 in which said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet.

Claim 4

A passive transponder as set forth in claim 2 wherein the distance over which the radiating elements extend from said self-inductive loop is substantially equal to or less than a quarter of the wave length of said first frequency.

Claim 5

A passive transponder as set forth in claim 1 in which point shaped portions (18) are provided at the connection points of said non-linear component with said self inductive loop.

Claim 6

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein the dielectric support comprises a watch bracelet (21).

Claim 7

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein the dielectric support comprises a watch bracelet (21).

Claim 8

A passive transponder as set forth in claim 5 wherein the antenna is moulded into said bracelet.

Claim 9

A passive transponder as set forth in claim 1 wherein the non-linear component is oriented across the bracelet.

Claim 10

A passive transponder as set forth in claim 5 in which said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet.

Claim 11

A passive transponder as set forth in claim 8 wherein the distance over which the radiating elements extend from said self-inductive loop is substantially equal to or less than a quarter of the wave length of said first frequency.

Claim 12

A passive transponder as set forth in claim 5 in which point shaped portions (18) are provided at the connection points of said non-linear component with said self-inductive loop.

Claim 13

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein the dielectric support comprises a watch dial.

Claim 14

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein the dielectric support comprises a watch dial.

Claim 15

A passive transponder as set forth in claim 11 in which said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet.

Claim 16

A passive transponder as set forth in claim 12 wherein the distance over which the radiating elements extend from said self-inductive loop is substantially equal to or less than a quarter of the wave length of said first frequency.

Claim 17

A passive transponder as set forth in claim 11 in which point shaped portions (18) are provided at the connection points of said non-linear component with said self-inductive loop.

Claim 18

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet, and wherein notches (22) are provided at junctions between the self-inductive loop and said radiating elements to partially limit an outer contour of said loop.

Claim 19

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting at a first frequency and receiving at a second frequency which is a harmonic of said first frequency, comprising: a dielectric support (11), an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating at said first frequency, wherein said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet, and wherein notches (22) are provided at junctions between the self-inductive loop and said radiating elements to partially limit an outer contour of said loop.

Claim 20

A passive transponder as set forth in claim 15 wherein the distance over which the radiating elements extend from said self-inductive loop is substantially equal to or less than a quarter of the wave length of said first frequency.

Claim 21

A passive transponder as set forth in claim 15 in which point shaped portions (18) are provided at the connection points of said non-linear component with said self-inductive loop.

Claim 22

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting a signal at a first discrete frequency and receiving a return signal at a second discrete frequency which is a harmonic of said first frequency, comprising: exclusively, a dielectric support (11), and an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path including said conductive portion and closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating exclusively at said first frequency and radiating a return signal exclusively at said second, harmonic frequency.

Claim 23

A passive transponder for seeking out persons by means of a combined transmitter-receiver capable of transmitting a signal at a first discrete frequency and receiving a return signal at a second discrete frequency which is a harmonic of said first frequency, comprising: exclusively, a dielectric support (11), and an antenna formed from a thin conductive sheet (12) fixed to said support and including a non-linear passive component (19) and a conductive portion (16) electrically parallel to said passive component to establish a direct current bias thereof, said antenna sheet defining a cutout portion (15) having an edge (17) which defines a conductive path including said conductive portion and closed by the passive component to form a self-inductive loop, said loop, together with the capacity of the passive component, providing a circuit resonating exclusively at said first frequency and radiating a return signal exclusively at said second, harmonic frequency.

Claim 24

A passive transponder as set forth in claim 18 in which said antenna comprises radiating elements (14a, b) extending from both sides of said self-inductive loop and formed from the same thin sheet.

Claim 25

A passive transponder as set forth in claim 19 wherein the distance over which the radiating elements extend from said self-inductive loop is substantially equal to or less than a quarter of the wave length of said first frequency.

Claim 26

A passive transponder as set forth in claim 18 in which point shaped portions (18) are provided at the connection points of said non-linear component with said self-inductive loop.