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High Hesitivity Magnetic Materials for Magnetic Toroid and Flat Dipole Antennas


TECHNOLOGY AREA(S): Air Platform, Materials/Processes, Sensors

ACQUISITION PROGRAM: PMA-234 Airborne Electronic Attack Program Office

OBJECTIVE: Develop a process to produce magnetic film materials with hesitivities well in excess of currently available materials for application in magnetic toroid and flat dipole antenna elements.

DESCRIPTION: High-performance magnetic loop antennas can presently be constructed by winding a tape of thin magnetic material into the form of a loop. The same materials can be used to fabricate flat magnetic dipoles. The magnetic materials that work best have extremely high hesitivity properties [1], high enough that the magnetic field can be sustained at ultra-high frequencies (UHF). The increasing need for higher-frequency performance is driving the need for higher hesitivities. Hesitivity [1, 2 and 4] is the definitive parameter that allows for efficient categorization of magnetic materials where it measures the maximum magnetic conductivity of the material in units of ohms per meter.

Currently, CoZrNb ferromagnetic thin film material provides the highest available bulk hesitivity on the order of 6,000,000. Hesitivities of a much higher order are greatly desired with a threshold of a factor of 10 improvement. Currently these magnetic materials are formed at the atomic level by vacuum deposition of a very thin layer on a dielectric carrier film, the thickness of the carrier film dilutes the overall bulk properties of the material when layered into an antenna element, thus reducing the overall performance.

The effective hesitivity properties of such an assembly can be improved with the development of magnetic materials with higher hesitivities, and the use of thinner substrates. The substrate material must withstand the high deposition temperatures without becoming brittle or breaking during the deposition process, which involves mechanically moving the film through the deposition chamber. The solution magnetic material should improve both of these factors at once to achieve a practical effective hesitivity of an order of magnitude or more higher than what is now available.

PHASE I: Determine the technical feasibility of constructing higher hesitivity materials on very thin carrier films. Determine the practical limits of hesitivity and carrier film thickness that could be attained. Demonstrate feasibility and determine and propose a candidate alloy to be produced and applied to wide-band antennas in Phase II.

PHASE II: Further develop candidate alloy prototype for production by a viable continuous process. Verify hesitivity on prototype samples.

PHASE III DUAL USE APPLICATIONS: Finalize the selected material production process and produce quantities required to manufacture wide-bandwidth antennas for use on ground and air vehicles. The foundry that would make this product could add it to a list of offerings to other customers. End users would apply the product to antennas for wide-bandwidth applications on aircraft, ground vehicles, and potentially on fixed structures at any location where low profiles are required.


    • Sebastian, T., Diaz, R., Auckland, D. & Daniel, C. (2013). A New Realization of an Efficient Broadband Conformal Magnetic Current Dipole Antenna. Presented at the IEEE Antennas and Propagation Meeting. Orlando, FL. Retrieved from


    • Sebastian, T. (2013). Magneto-dielectric Wire Antennas – Theory and Design. Arizona State University, PhD Dissertation, May 2013.


    • Diaz, R. (2014). Multi-function pseudo-conductor antennas. US Patent 8,686,918 B1


  • Auckland, D., Daniel, C. & Diaz, R. (2014). A New Type of Conformal Antennas Using Magnetic Materials. IEEE Military Communications Conference

KEYWORDS: Antennas; wide-bandwidth antennas; low profile antennas; conformal antennas; magnetic materials; magnetic hesitivity

  • TPOC-1: 301-342-9167
  • TPOC-2: 301-757-8923

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