Abstract: The invention relates to a special type of magnetic tag that serves both as an identifier of the article to which it is attached and as an antitheft device. Identification comes about through the use of an array of individual magnetic elements that are closely spaced, preferably along and perpendicular to an amorphous wire or strip. The wire or strip forms an integral part of the identification array and can be used as an anti-theft device to trigger an alarm when activated by an external field from a magnetic gate. The array may be personalized (coded) by leaving out elements of the array or by driving selected elements to saturation while others remain demagnetized. The elements can also be in the form of a double array to constitute `l`s and `0`s to form a code. Reading of the elements (code) is accomplished with a special reading head consisting of one or more small magnetic circuits coupled to one or more pickup loops utilizing, in some cases, the Matteucci effect.

Abstract: The present apparatus is a mobile shopping cart that can automatically keep track of objects selected and carried in the cart and provide a customer using the cart information like the total price of the items carried. The cart has a radio frequency cart base station with a cart antenna connected to a radio frequency cart transceiver. Various novel embodiments of the invention produce a radio frequency field within the shopping cart that is used to communicate with radio frequency tags on objects carried in the cart. The tags contain information about the respective carried object to which the tags are attached. A program function executed by the cart circuit and/or computer controls the cart transceiver to interrogate radio frequency tags within the radio frequency field, i.e. inside the cart to gain information about the carried objects. Tags on objects external to the cart are not interrogated.

Abstract: An inexpensive multibit magnetic tag is described which uses an array of amorphous wires in conjunction with a magnetic bias field. The tag is interrogated by the use of a ramped field or an ac field or a combination of the two. The magnetic bias is supplied either by coating each wire with a hard magnetic material which is magnetized or by using magnetized hard magnetic wires or foil strips in proximity to the amorphous wires. Each wire switches at a different value of the external interrogation field due to the difference in the magnetic bias field acting on each wire.

Abstract: A transponder is disclosed comprising a resonant RLC circuit with one or more components that can be connected or disconnected non-destructively using switches that respond to an externally applied magnetic field. The switching in or out of the components causes a change in the resonant frequency of the original RLC circuit that is detected by the base station sweeping a carrier signal through a range of frequencies to detect a returned signal that changes when the carrier signal frequency matches the resonant frequency of the resonant circuit/tag. The resonant frequency changes when one or more of the circuit components is connected or disconnected. Each switch transfers at a unique magnetic field intensity so that electrical contact is achieved at a predetermined value of an externally applied magnetic field. The detected changes are used to create a code that is used to pass information from the resonant circuit/tag to the base station.

Abstract: A detector of thermal energy is composed of an insulating substrate such as glass or sapphire coated with a thin film deposit of a slant-angle deposited metal preferably a transition element such as Ti, V, Cr, Co, Ni, Ta, W, U, Os, Ir, Pt and Mb exhibiting a transverse thermoelectric effect in response to a thermal energy gradient normal to the plane of the deposit. A layer of an electrical insulating material which is thermally conductive is deposited upon the thin film deposit, using materials such as SiO.sub.2, SiO, perylene, etc. Another thin film deposit of a slant-angle film is deposited on top of the insulating material. A stack of alternate slant-angle thermoelectric elements and electrical insulating layers is formed to a depth at which the thermal gradient in the lowest slant-angle deposit is marginally advantageous. An input light, laser or other heat producing beam is applied to the upper layer of the stack.