Platform-Enhanced, Wideband, Directional, and Dual-Polarized Electrically-Small Antennas for HF, VHF, and UHF
Abstract
Examining the platform modes shown in Fig. 6 reveals that all the elementary radiation patterns needed to support the three primary HF modes of communication (NVIS, groundwave, and skywave) are available from these modes. Additionally, because of the relatively low Q of these modes, their efficient excitation is expected to result in a wideband operation. Therefore, the task of designing the antenna boils down to designing the coupling mechanism to excite the necessary mode for each operation with sufficient bandwidth. The technical approach of the proposed research is based on exploiting the natural platform modes as building blocks for designing directional, dual-polarized, wideband, and UWB electricallysmall antennas. The proposed project involves antenna designs at HF and VHF/UHF frequency bands. In the HF band, the focus will be exclusively on design of platform-based antennas and developing techniques for efficiently exciting the mode or combination of modes that provides the desired response type (e.g. a directional antenna in the azimuth plane). To illustrate this concept, let us revisit the simple platform shown in Fig. 2. Fig. 6 shows the current distributions of the first six characteristic modes of this platform and their associated radiation patterns. Modes 1-3 radiate similar to electric dipoles oriented respectively along the ??, ??, and ?? directions and modes 4-6 radiate similar to magnetic dipoles oriented respectively along the ??, ??, and ?? directions. These six modes are the elementary building blocks that can be used to obtain directional or dual-polarized radiation patterns for NVIS, groundwave, and skywave HF communications (see descriptions for Tasks 4 and 6 in Section 6). Additionally, because these modes have lower Q values compared to any platform-mounted antenna that offers similar radiation properties, their efficient excitation is expected to results in wider bandwidths.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 10, 2016
- Source ID
- N000141612098
Entities
People
- Nader Behdad
Organizations
- Office of Naval Research
- United States Navy
- University of Wisconsin System