Gregory C. Tavik

Preliminary Investigations of a Low-Cost Ultrawideband Array Concept

A design concept is presented that achieves ultra wideband (UWB) array performance with significantly fewer elements than the traditional approach of using a single wideband antenna element type to fully populate the array. Starting from a conventional 8:1 bandwidth array design of a given aperture size, an array of equivalent aperture and bandwidth is created using scaled elements of three different sizes. This wavelength-scaled equivalent array has fewer than 18% of the original element count, i.e., roughly 6-times fewer elements, a similar reduction in weight, and most importantly, a significant reduction in electronics required to feed the array. If proven viable, array architectures of this type could make UWB arrays significantly more cost effective. In this preliminary numerical study, rigorous full-wave simulation tools are used to test the performance of small but informative wavelength-scaled array configurations of flared-notch radiators for the single-polarization case.

Wideband multifunction array architectures using wavelength-scaled radiating elements

There has been a significant increase in developing multifunction wideband arrays to consolidate the large number of narrowband reflector antennas on US Navy ships. However, the use of conventional methods results in a need for an extremely large number of radiating elements to populate these arrays resulting in a complex and costly multifunction array. We propose architectures that use wavelength-scaled arrays in combination with asymmetrical distribution of arrays to reduce the number of radiating elements by more than a factor of two as well as ease bandwidth requirements. Additionally, a combination of rectangular and square apertures is used, where possible to help further reduce the number of simultaneous beams from any section of the full array. These proposed architectures are capable of providing eight different beams from a single wideband multifunction array.

Low-cost phased array antenna for satellite communications on mobile earth stations

Future US Navy ships are expected to use multifunction, low radar cross section (RCS) phased array antennas for satellite communications. In this paper, we present a unique phased array concept in which a single planar array antenna (on a mobile earth station) can be used to communicate simultaneously with several geostationary (GEO) satellites by generating multiple independent beams. This array will have full electronic beam scanning capability in the azimuth direction with fixed beam positions in the orthogonal (elevation) plane using one or at most two hard-wired squints without the need for redesigning the antenna for different earth station locations. The proposed technique will reduce the cost and complexity of phased array antennas designed for mobile earth stations.

Low-cost multibeam phased array antenna for communications with GEO satellites

In this article, we have shown the development of a unique design concept in which a single planar array antenna consisting of N × M elements on a mobile earth station, such as a navy ship, will require only M phase shifters (for each beam) and one or two hard-wired squints to communicate with several GEO satellites simultaneously by generating multiple independent beams. Our simplified design enables a reduction in both the cost and the complexity of a PAA. This unique concept reduces complexity by requiring full scan capability only in the azimuth plane, thereby reducing the number of phase shifters from NM to M for each beam. At the same time, only one or two hard-wired squints are used in the elevation plane, further reducing the complexity and thus the cost of development of such a PAA.