Electrically small, mixed modal antenna (MMA) array for aerospace applications

Based on the modal antenna analysis due to D.M. Grimes (see Physica 20D, p.285-302, 1986) near-field interaction between elements of an antenna ensemble wave used to produce resonant, directed radiation from a small antenna. By previous theory, mixed TE and TM modes are found to be orthogonal and, therefore, a small resonant and/or directional antenna is not possible. The authors recount the analysis showing that time-average power is orthogonal and reactive power is not. Nonorthogonal reactive power suggests that a small, resonant, directive antenna may be possible. Such an antenna is potentially useful for aerospace applications. The authors report experimental progress to date. In agreement with the theory, it was found that the resonant frequency depends on the relative values of driving currents; the resonant frequency of the magnetic dipole decreased more than 30% when a 50- Omega resistive pad loaded the electric dipole.<
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