Frequency Independent Distributed Impedance Magnetic Flux Channel Antennas

Frequency Independent Distributed Impedance Magnetic Flux Channel Antennas Frequency Independent Distributed Impedance Magnetic Flux Channel Antennas The Opportunity: Magnetic Flux Channel (MFC) antennas conformal to a conducting surface have been recently demonstrated [1-4] to derive all the theoretical benefits of antennas carrying true magnetic currents. The intrinsically large Bandwidth of these antennas in the HF to UHF range can exceed by three orders of magnitude the Bandwidth of metal-and-dielectric antennas constrained to the same conformal volume. As a result even in the presence of the unavoidable loss associated with dispersive permeable materials (ferromagnetic metals and ferrimagnetic ceramics) the MFC antennas Efficiency Bandwidth Product (EBWP) can exceed that of the metal-dielectric alternative by two orders of magnitude. Such a large intrinsic EBWP in a conformal antenna is unprecedented and opens the door to field truly broad band multi-function conformal apertures for DoD applications. The Challenges: Although in theory and from the recent demonstrations reported in [2] and [3] it is clear that Magnetic Flux Channel antennas constitute the ideal conformal radiator, their emergent nature is their biggest challenge. We simply do not have a long engineering history of their application to standard antenna problems. For instance, are electrically small MFC antennas more difficult to match than conventional antennas? As we show in the Approach section the answer is in fact the opposite; using the fundamental Bode-Fano criterion and the derived Match Bandwidth formulation of Best and Yaghjian it can be shown that MFC antennas are easier to match than conformal metal-dielectric antennas. The answer to other questions such as their high-power handling capability will require experimental verification; but back of the envelope calculations suggest the verdict will again be in favor of the MFC antenna. The key question is: Is the impact MFC antennas can have on DoD systems significant enough to justify their full development? We believe the answer is positive and further that it will lead to their eventual adoption as the standard DoD conformal antenna. This SBIR topic provides the means to demonstrate that answer. The extremely large intrinsic EBWP of MFC antennas suggests they should yield absolutely conformal (cavity-less) frequency independent structures with extremely stable pattern and impedance bandwidths, requiring minimal matching networks (except for, possibly, a balun.) Proving this for both spiral and log-periodic geometries is the goal of our proposed project.