Conventional multiband antennas suffer from strong interactions among different operating frequencies, complex configurations, low bandwidth, and reduced efficiencies. A design concept for a multibeam multiband antenna in wireless devices is proposed in this paper. The design concept provides a promising approach to augment transmission and reception. The principle of design involves a primary radiating element embedded in a triplate conformation which excites a passive array of multiple frequency secondary radiators, forming a frequency selective structure in triplate (FSST). The higher order mode behavior of the parent antenna characterizes the design of FSST placed in its nearfield. The mathematical modeling and analysis of the design methodology is also presented. As proof of concept, the proposed design methodology is validated with simulations and experiments at four unlicensed communication bands and the results are compared.

Quaternary processes and environmental changes are often difficult to assess in remote subantarctic islands due to high surface erosion rates and overprinting of sedimentary products in locations that can be a challenge to access. We present a set of high-resolution, multichannel seismic lines and complementary multibeam bathymetry collected off the eastern (leeward) side of the subantarctic Auckland Islands, about 465 km south of New Zealand's South Island. These data constrain the erosive and depositional history of the island group, and they reveal an extensive system of sediment-filled valleys that extend offshore to depths that exceed glacial low-stand sea level. Although shallow, marine, U-shaped valleys and moraines are imaged, the rugged offshore geomorphology of the paleovalley floors and the stratigraphy of infill sediments suggests that the valley floors were shaped by submarine fluvial erosion, and subsequently filled by lacustrine, fjord, and fluvial sedimentary processes.

New high-resolution multibeam swath bathymetry along the east coast of the Auckland Islands is combined with subaerial topography and evaluated in the context of Quaternary glaciation of the islands. The marine geomorphology represents a mixture of past and current processes so that submerged glacial features are more evident in some areas than others. Fjords in the central and southern parts of the coastline are characterized by well-preserved terminal moraines and other glacial features while fjords to the north tend to have more subdued glacial features and a smoother seabed. This is the farthest north record yet established of extensive sub-Antarctic glaciation, relative to the position of the modern sub-Antarctic and Polar Front. This is the first analysis of detailed sea floor geomorphology in the area and provides a starting point for new studies of paleoclimate and past glaciations.