Invention Grant
- Patent Title: VLF transmit antenna system, method and apparatus
- Patent Title (中): VLF发射天线系统,方法和装置
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Application No.: US14358747Application Date: 2012-11-19
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Publication No.: US09231799B2Publication Date: 2016-01-05
- Inventor: Michael James Roper , Vladimir Puzakov
- Applicant: VITAL ALERT COMMUNICATION INC.
- Applicant Address: CA Thornhill, Ontario
- Assignee: VITAL ALERT COMMUNICATION INC.
- Current Assignee: VITAL ALERT COMMUNICATION INC.
- Current Assignee Address: CA Thornhill, Ontario
- Agency: Norton Rose Fulbright Canada LLP
- Agent Maya Medeiros
- International Application: PCT/CA2012/001091 WO 20121119
- International Announcement: WO2013/071426 WO 20130523
- Main IPC: H04B13/02
- IPC: H04B13/02 ; H04L25/49 ; H01Q7/00 ; H04B5/00 ; H01Q1/04

Abstract:
There is provided a Very Low Frequency (VLF) transmit antenna system, method, and apparatus for creating a magnetic field at low frequencies suitable for communications through the earth or other thick, solid barriers. At least two loop antennas are arranged such that a magnetic field of each one of the at least two loop antennas passes through each remaining one of the at least two loop antennas, thereby closely coupling the at least two loop antennas. A full bridge Pulse Width Modulated transmitter is directly connected to each loop antenna for driving the latter. When a loop of a given loop antenna is broken and its magnetic field collapses, the transmitters connected to the remaining loop antennas increase the current in the remaining loops to maintain a constant magnetic field.
Public/Granted literature
- US20140314129A1 VLF TRANSMIT ANTENNA SYSTEM, METHOD AND APPARATUS Public/Granted day:2014-10-23
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