D.S Prinsloo

Design of an active dual-mode antenna with near hemispherical Field of View coverage

A dual-mode antenna design, utilizing a combination of differential- and common-mode excitations, is presented. This antenna offers the possibility to complex-combine both modes in order to obtain a near-hemispherical Field of View (FoV) coverage. A Single-Ended (SE) to Mixed-Mode (MM) transformation model is introduced to determine the MM radiation characteristics of this antenna from SE scattering parameters and embedded element patterns. A FoV of ±90°, from zenith, is achieved with a maximum gain variation of 5 dB.

Quad-mode antenna for wide-scan sparse arrays

A conical quad-mode antenna excited through four orthogonal transverse electromagnetic modes is presented. The radiation characteristics of each mode are validated through measurements, illustrating the complimentary nature of the four far-field radiation patterns through which near-hemispherical field-of-view coverage can be achieved.

Beamforming strategies for active multi-mode antennas: Maximum gain, Signal-to-Noise ratio, and polarization discrimination

The performance of a dual-polarized quad-mode antenna, representing a potential array antenna element for wide scan-angle applications, is assessed. This analysis is carried out by investigating the utilization of the four available Transverse Electromagnetic (TEM) excitation modes, when beamforming for maximum gain, Signal-to-Noise ratio (SNR), and polarization discrimination whilst retaining minimum noise.

Conical quad-mode antenna with integrated tapered slot antennas for wide-field polarimetry

This paper presents a conical quad-mode antenna for irregular sparse antenna arrays. The antenna integrates tapered slot antennas with two orthogonal dipole antennas and a conical monopole element to achieve good polarimetric performance over an ultra-wide field-of-view coverage. It is shown that the presented antenna element is able to detect two orthogonal field components up to scan angles of 80° from zenith over a 50% relative bandwidth.

Generalized Multimode Scattering Parameter and Antenna Far-Field Conversions

A general technique is presented to transform multimode and mixed-mode scattering parameters (S-parameters) between arbitrary sets of equivalent passive N-port networks, and transform antenna far-fields between N-port antennas with different sets of multimode or single-ended excitations. The technique makes use of simple transformation matrices, and makes provision for general multimode ports, coupled and uncoupled multiconductor transverse electromagnetic ports, and mixed-mode networks containing both differential ports and single-ended ports. A quadraxially fed multimodal antenna is analyzed as example.