A mechanically based magneto-inductive transmitter with electrically modulated reluctance

Strachen, Nathan; Booske, John H.; Behdad, Nader

doi:10.1371/journal.pone.0199934

Cited by 20 publications

(7 citation statements)

References 12 publications

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“…We thus have a specific amount of radiated power, P r , for a maximum amount of stored energy, W max , and we can calculate the antenna's quality factor as Q = ωW max /P r . Fundamental limits of antennas 22,23 tie an antenna's quality factor to its electrical size as Q = 1/(ka) 3 , where a is the radius of smallest surrounding sphere and k = 2π/λ is the wave number. That means the smaller the antenna, the more energy we need for a given radiated power to be stored.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Finally, the spark-gap oscillators were replaced by the Alexanderson alternator (a mechanical structure based on a rotating permanent magnet) in 1904. Surprisingly, many variants of Alexanderson alternator have been suggested after more than a century [2][3][4][5][6][7][8] , in response to a DARPA call for ELF and VLF sources in recent years. Such mechanical generators (mechtenna), however, still have the same shortcomings as the original design, such as large size, massive power consumption, hard to modulate and transmit information, synchronization, noise, vibration, and durability problem of a mechanical structure.…”

mentioning

confidence: 99%

“…Meanwhile, we alternate the direction of flux between free space and a medium with high permeability. The permeability of the magnetic material near the permanent magnet varies by adjusting the current through a control coil, depending on the B-H curve of the magnetic material 3 .…”

mentioning

confidence: 99%

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New Way of Generating Electromagnetic Waves

Hosseini-Fahraji¹,

Manteghi²,

Ngo³

2020

Preprint

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This paper presents a new method for generating low-frequency electromagnetic waves for navigation and communication in challenging environments, such as underwater and underground. The main idea is to store magnetic energy in two different spaces using the interaction between a permanent magnet and a magnetic material. The magnetic reluctance of the medium around the permanent magnet is modulated to change the magnetic flux path. The nonlinear properties of magnetic material as a critical phenomenon are used for effective modulation. As a result, a time-variant field is generated by the modulation of the permanent magnet flux. This non-resonant time-variant characterization means that the transmitter is not bound to the fundamental limits of the antennas and can transmit higher data rates. A prototype transmitter as a prove-of-concept is designed and tested based on the proposed idea. Compared to the rotating magnet, the prototyped transmitter can modulate 50% of the stored energy of the permanent magnet with much lower power consumption.

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Section: Theoretical Backgroundmentioning

confidence: 99%

mentioning

confidence: 99%

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New Way of Generating Electromagnetic Waves

Hosseini-Fahraji¹,

Manteghi²,

Ngo³

2020

Preprint

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show abstract

“…This modulation typically consumes a significant amount of energy per bit since a slow-down/speed-up operation must be used for data transmission, although regenerative braking methods may be considered. Alternatively, mu-metal shielding and switching circuits can also be invoked [24] for achieving amplitude modulation while the rotor maintains a constant rotational speed.…”

Section: Introductionmentioning

confidence: 99%

Magneto-Mechanical Transmitters for Ultralow Frequency Near-Field Data Transfer

Thanalakshme

Kanj

Kim

et al. 2022

IEEE Trans. Antennas Propagat.

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Electromagnetic signals in the ultralow frequency (ULF) range below 3 kHz are well suited for underwater and underground wireless communication thanks to low signal attenuation and high penetration depth. However, it is challenging to design ULF transmitters that are simultaneously compact and energy efficient using traditional approaches, e.g., using coils or dipole antennas. Recent works have considered magneto-mechanical alternatives, in which ULF magnetic fields are generated using the motion of permanent magnets, since they enable extremely compact ULF transmitters that can operate with low energy consumption and are suitable for humanportable applications. Here we explore the design and operating principles of resonant magneto-mechanical transmitters (MMT) that operate over frequencies spanning a few 10 s of Hz up to 1 kHz. We experimentally demonstrate two types of MMT designs using both single-rotor and multirotor architectures. We study the nonlinear electro-mechanical dynamics of MMTs using point dipole approximation and magneto-static simulations. We further experimentally explore techniques to control the operation frequency and demonstrate amplitude modulation up to 10 bits-per-second. We additionally demonstrate how using oppositely polarized MMT modules can permit systems that have low dc-field but do not sacrifice the ac magnetic field produced.

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“…This modulation typically consumes a significant amount of energy per bit since a slow down/speed up operation must be used for data transmission, although regenerative braking methods may be considered. Alternatively, mu-metal shielding and switching circuits can also be invoked [22] for achieving amplitude modulation while the rotor maintains a constant rotational speed.…”

Section: Introductionmentioning

confidence: 99%

Magneto-Mechanical Transmitters for Ultra-Low Frequency Near-field Communication

Thanalakshme,

Kanj,

Kim

et al. 2020

Preprint

View full text Add to dashboard Cite

Electromagnetic signals in the ultra-low frequency (ULF) range below 3 kHz are well suited for underwater and underground wireless communication thanks to low signal attenuation and high penetration depth. However, it is challenging to design ULF transmitters that are simultaneously compact and energy efficient using traditional approaches, e.g., using coils or dipole antennas. Recent works have considered magnetomechanical alternatives, in which ULF magnetic fields are generated using the motion of permanent magnets, since they enable extremely compact ULF transmitters that can operate with low energy consumption and are suitable for humanportable applications. Here we explore the design and operating principles of resonant magneto-mechanical transmitters (MMT) that operate over frequencies spanning a few 10's of Hz up to 1 kHz. We experimentally demonstrate two types of MMT designs using both single-rotor and multi-rotor architectures. We study the nonlinear electro-mechanical dynamics of MMTs using point dipole approximation and magneto-static simulations. We further experimentally explore techniques to control the operation frequency and demonstrate amplitude modulation up to 10 bits-per-second.

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A mechanically based magneto-inductive transmitter with electrically modulated reluctance

Cited by 20 publications

References 12 publications

New Way of Generating Electromagnetic Waves

New Way of Generating Electromagnetic Waves

Magneto-Mechanical Transmitters for Ultralow Frequency Near-Field Data Transfer

Magneto-Mechanical Transmitters for Ultra-Low Frequency Near-field Communication

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