Multi-band linear and circular polarized, electrically small, near field resonant parasitic antennas

We have developed a variety of electrically small, near-field resonant parasitic (NFRP) antennas. Several examples and their performance characteristics will be presented. These are based on capacitively-loaded loop (CLL) NRFPs with both electric and magnetic couplings to the driven element; both varieties will be compared and contrasted. Integrating multiple NFRP CLL elements with coaxially-fed electrically-small monopoles or semi-circular loop antennas, both single- and dual-band, linearly (LP) and circularly polarized (CP) antenna designs are achieved. The CP designs rely on two orthogonal equivalent magnetic dipoles tuned at slightly different resonance frequencies to achieve the requisite 90° phase shift between them at an intermediate frequency. Two driven monopoles are required for the electrically-coupled version; one driven semi-loop antenna is required for the magnetically-coupled version. However, only the electrically-coupled design has enough tuning parameters to lead to a dual-band, NFRP CLL-based CP antenna. This dual-band CP design will be discussed in our presentation.