An Introduction to Ferrite Rod Antenna

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(No Transcript)
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Overview

• Ferrite rod antennas are tiny magnetic loop
  antennas that are utilised in AM broadcast
  transistor radios for medium and long waveband
  reception as well as RFID applications. It is
  constructed using a ferrites rod or bar and
  contains a coil coiled around the ferrite rod
  using a variable tuning capacitor in the radio
  electronics.

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How does Ferrite Rod Antenna work?

• Its performance and frequency responsiveness are
  limited due to losses in the ferrite core. As a
  result, the antenna functions at frequencies
  ranging from 2 to 3 MHz.
• A ferrite rod antenna is mostly used to receive
  lower frequency transmissions ranging from 50hz
  to 50khz. It functions as transmitting antennas
  for applications that require minimal power and
  efficiency. If the power levels are high, the
  ferrite rod may experience heat dissipation
  problems.
• The tiny size and convenience, on the other hand,
  contribute to its advantages and raise its demand
  for RFID applications.

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Design

• The antenna may also be constructed using other
  parameter combinations. As a result, a shorter
  and broader coil with more turns can provide the
  same output voltage as a longer and thinner coil
  with fewer turns and greater magnetic
  permeability.
• Because each arrangement will employ various
  materials, the price may vary. The major goal is
  to deliver a target output voltage and power
  while keeping restrictions like physical size and
  Q factor in mind. This might assist you in
  determining the optimum configuration that has
  the lowest cost and meets all design limitations.

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Ferrite Rod Antenna Parameters

• The two most significant characteristics of a
  ferrite rod antenna are the tuned circuit's 'Q'
  and the radiation resistance. These
  characteristics govern where the antennas can be
  used as well as the design of the circuits that
  utilise them.

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Importance of The Q Parameter

• The 'Q' or Quality parameter of the circuit
  design in which the ferrite rod antenna coil is
  positioned is a significant issue. To perform
  efficiently, the circuit must have a high Q at
  the frequencies where the antenna would operate.
• If the frequency is a few hundred kHz, a medium
  permeability material will be put in the ferrite
  rod antenna to assist maintain a Q value of 1000
  or so. At this point, the antenna must be tuned
  to function at a higher frequency.
• Because the magnetic circuit is open, the Q value
  of the ferrite core in the rod will likewise be
  bigger than the material value. This number is
  proportional to the maximum operational distance.

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How is it useful for Radiation Resistance?

• If the antenna is not ferrite, it has a small
  loop that is less than a wavelength in length and
  has a low radiation resistance. As a result, the
  losses caused by wire resistance would be
  exceedingly large.
• To address this, a ferrite core is put in the
  coil to boost the radiation resistance of the
  ferrite rod antenna. This lowers the radiation
  resistance and reduces resistive losses caused by
  the wire.

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Continue

• While the ferrite rod is helpful for increasing
  radiation resistance in antennas, it introduces
  additional losses. The energy necessary to alter
  the magnetic alignment in the granular structure
  of the ferrite core is absorbed by the ferrite.
• If the frequency is increased, the number of
  changes increases, and hence the losses increase.
  As a result, ferrite rod antennas are only
  employed at low frequencies and not at higher
  frequencies.

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Conclusion

• In terms of efficiency, frequency, and tuning, a
  ferrite rod antenna is a solid choice. Their
  popularity and demand as RF antennas for portable
  radios is increasing worldwide.
• Alisha Coils Transformers designs Ferrite Rod
  Antennas using quality and new technology to give
  our customers with customised solutions. Our
  strength is in-house ferrite core manufacturing,
  which allows us to assure product quality and
  timely delivery.

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Thank You

• If you need more assistance, you can feel free to
  connect with our experts who will take you
  through our wide range of ferrite products
  available for several applications. Contact us to
  learn more.

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www.cosmoferrites.com
91-11 4939 8800