Patent US5373301A successfully refreshed from Google Patents.
US5373301A
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Transmit and receive antenna having angled crossover elements
Assignee: Checkpoint Systems Inc
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Filing: 1993-01-04
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Granted: 1994-12-13
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Expires: 2013-01-04
Abstract
Abstract An antenna for simultaneously transmitting and receiving electromagnetic energy is disclosed. The antenna includes first and second transmit elements and a transmitter for supplying a first current to the first transmit element and a second current to the second transmit element such that the first and second transmit elements radiate electromagnetic fields. Preferably, the supplied first and second currents are substantially equal. The antenna also includes a sensor for sensing differences between currents flowing through the first and second transmit elements. The differences are caused by an electromagnetic field external to the antenna such that the antenna effectively receives the external electromagnetic field by sensing the current differences.
Inventors
- 👤 John H. Bowers
- 👤 Philip J. Lizzi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:34
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/12; H01Q1/22; H01Q1/2208; H01Q1/2216; H01Q11/00; H01Q11/12; H01Q7/00; H01Q7/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
99 words
An antenna for simultaneously transmitting and receiving electromagnetic energy, comprising: first and second transmit elements; means for supplying a first current to the first transmit element and a second current to the second transmit element such that the first and second transmit elements radiate electromagnetic fields, wherein the supplied first and second currents are substantially equal; and means for sensing differences between currents flowing through the first and second transmit elements, wherein the differences are caused by an electromagnetic field external to the antenna such that the antenna effectively receives the external electromagnetic field by sensing the current differences.
Claim 2
Dependent Claim
99 words
An antenna for simultaneously transmitting and receiving electromagnetic energy, comprising: first and second transmit elements; means for supplying a first current to the first transmit element and a second current to the second transmit element such that the first and second transmit elements radiate electromagnetic fields, wherein the supplied first and second currents are substantially equal; and means for sensing differences between currents flowing through the first and second transmit elements, wherein the differences are caused by an electromagnetic field external to the antenna such that the antenna effectively receives the external electromagnetic field by sensing the current differences.
Claim 3
Dependent Claim
106 words
The antenna of claim 1, wherein the first and second transmit elements each comprises an antenna loop having an axis, a first section having first and second ends, and a second section extending between the first and second ends of the first section at a predetermined angle relative to the axis, the first and second transmit elements being generally parallel to each other and spaced slightly apart along the respective second sections, the predetermined angle of the first transmit element and the predetermined angle of the second transmit element being substantially equal to a value other than 90° such that an angled null zone is achieved.
Claim 4
Dependent Claim
35 words
The antenna of claim 2, wherein the first section comprises first and second sides each generally parallel to the axis, and a third side generally perpendicular to and extending between the first and second sides.
Claim 5
Dependent Claim
118 words
The antenna of claim 1, wherein the first and second transmit elements each comprises an antenna loop having an axis, first and second sides each generally parallel to the axis, a third side generally perpendicular to and extending between the first and second sides, and a fourth side extending between the first and second sides at a predetermined angle relative to the axis, the first and second transmit elements being generally parallel to each other and spaced slightly apart along the respective fourth sides, the predetermined angle of the first transmit element and the predetermined angle of the second transmit element being substantially equal to a value other than 90° such that an angled null zone is achieved.
Claim 6
Dependent Claim
14 words
The antenna of claim 1, wherein the first transmit element comprises an antenna loop.
Claim 7
Dependent Claim
19 words
The antenna of claim 1, wherein the first and second transmit elements comprise first and second antenna loops, respectively.
Claim 8
Dependent Claim
17 words
The antenna of claim 6, wherein the first and second antenna loops comprise a single conductive wire.
Claim 9
Dependent Claim
84 words
The antenna of claim 1, wherein the first transmit element is substantially equal in area to the second transmit element, and wherein the means for supplying the first and second currents comprises means for supplying the first current in a first angular direction to the first transmit element and for supplying the second current in a second angular direction opposite the first angular direction to the second transmit element, such that far field cancellation of electromagnetic fields generated by the antenna is substantially achieved.
Claim 10
Dependent Claim
106 words
The antenna of claim 1, wherein the sensing means comprises a transformer having a primary winding, the transformer being connected to the first and second transmit elements such that current in the first transmit element flows through the transformer primary winding in a first direction and current in the second transmit element flows through the transformer primary winding in a second direction opposite the first direction, such that electromagnetic flux generated by the transformer is zero when the currents flowing through the first and second transmit elements are equal and not zero when the currents flowing through the first and second transmit elements are not equal.
Claim 11
Dependent Claim
120 words
An antenna for simultaneously transmitting and receiving electromagnetic energy, comprising: a primary antenna; a non-radiating load circuit having an impedance substantially equal to an impedance of the primary antenna; means for supplying a first current to the primary antenna such that the primary antenna radiates electromagnetic fields; means for supplying a second current to the non-radiating load circuit wherein the supplied second current is substantially equal to the first current supplied to the primary antenna; and means for sensing differences between currents flowing through the primary antenna and the non-radiating load circuit, wherein the differences are caused by an electromagnetic field external to the antenna such that the antenna effectively receives the external electromagnetic field by sensing the current differences.
Claim 12
Dependent Claim
120 words
An antenna for simultaneously transmitting and receiving electromagnetic energy, comprising: a primary antenna; a non-radiating load circuit having an impedance substantially equal to an impedance of the primary antenna; means for supplying a first current to the primary antenna such that the primary antenna radiates electromagnetic fields; means for supplying a second current to the non-radiating load circuit wherein the supplied second current is substantially equal to the first current supplied to the primary antenna; and means for sensing differences between currents flowing through the primary antenna and the non-radiating load circuit, wherein the differences are caused by an electromagnetic field external to the antenna such that the antenna effectively receives the external electromagnetic field by sensing the current differences.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-12 | 1998-06-13 | 1998-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-12 | 2002-06-13 | 2002-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-12 | 2006-06-13 | 2006-12-13 | $7700.00 | Window Closed / Lapsed |