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A circular monopole antenna fed with a coplanar waveguide is designed as an ultra-wideband (UWB) antenna for ground-penetrating radar. The performance of the antenna is enhanced by adding an electromagnetic band gap (EBG) surface on one side and a monopole director on the other side. The EBG surface can be a single-resonance structure or dual or multi-resonance structure for wider bandwidth. The enhanced design shows higher and flatter gain across the wideband, with different levels of improvements, depending on the choice of the additional layers, which also impacts the overall profile of the antenna. Simulation results of a number of designs are presented, along with measurement results of one design. Comparison of measured and simulated results is presented and shows good agreement. The target frequency band for the design is 0.7 3.0 GHz., The original document contains color images.

This report outlines basic research (6.1) work performed in the antenna area within the Antennas and RF Technology Integration Branch. The work is done with Army applications as the goal for transitioning this research to the field. The areas identified in this research represent topics at the cutting edge of technology in antennas and electromagnetics that is being pursued by academic, industrial, and Government organizations. In this effort, the US Army Research Laboratory (ARL) is reaching out to such organizations for productive collaboration., The original document contains color images.

The ability to hydrolyze keratin, a rigid and strongly cross-linked protein in the waste of poultry feather and sheep wool, has made keratinase production by microorganisms highly important to the biotechnological industry. A proteindegrading bacterium (C4) was isolated from compost. Based on morphology and biochemical tests, along with 16S rRNA sequencing, the isolated C4 was tentatively identified as Bacillus sp. C4 (2008). The proteolytic activity of the Bacillus sp. C4 strain was broadly specific; it degraded keratinous and non-keratinous proteins to different degrees. Pea pods as substrate generated the highest protease production, followed by soybean meal and sheep wool. Notwithstanding, using wool keratin as a sole source of carbon and nitrogen yielded the highest level of soluble proteins. Furthermore, the C4 bacterium grew well, and produced a significant level of keratinase when using wool and feather as substrates. Supplementing the medium with yeast extract and peptone shortened the time required for feather degradation, but delayed the onset of the wool keratin hydrolysis with two days. The predominant amino acids released in feather hydrolysate were tyrosine, phenylalanine, and histidine. In contrast, the wool lysate was rich in aspartic acid, methionine, tyrosine, phenylalanine, histidine, and lysine. Results established that utilizing the C4 strain for keratin degradation in waste management holds considerable potential.

The application of carbon nanotube (CNT) materials to produce lightweight, flexible, and durable alternatives to existing and future Army antenna designs is explored through fabrication and measurement of a variety of CNT thread and sheet antenna designs. A variety of CNT thread/rope dipole and loop antennas are fabricated, measured, and compared with a standard copper dipole antenna. An aperture-coupled patch antenna composed of CNT sheet material, is fabricated, measured, and compared with a standard copper patch antenna. Finally, a meshed patch antenna composed of interwoven CNT threads is developed and simulated as a concept for a multifunctional communications antenna and reactive gas sensor., The original document contains color images.

A reconfigurable polarization antenna includes a microwave dielectric substrate having a ground plane that has a centrally located slot with five conducting patches, four of which form an evenly spaced apart perimeter group with a gap between each and the fifth, centrally positioned conducting patch. A conducting pad is positioned in each gap and is connected via a switch to the ground plane. A microstrip feed line including a short stub is positioned on the opposite side of the substrate and electromagnetically coupled to the slot. The polarization of the antenna is reconfigured by a selection of an on or off state of each of said switches.

A dual-band, dual-orthogonally-polarized antenna element includes a dielectric substrate having a conductor layer that includes a square ring slot and a shorted square ring, with each having a pair of orthogonal feed points. The shorted square ring is fed with coaxial probe feeds, while the square ring slot feeds striplines terminated in open-circuited stubs for coupling energy to each pair of orthogonal feed points. The first and second stripline feeds are not coplanar in order that each stub terminates past a center point of the element. The square ring slot operates as a high frequency band radiator and the shorted square ring operates as a low frequency band radiator, and both bands radiate substantially simultaneous dual-orthogonally-polarized modes. The modes can be any combination of dual-Circular Polarization (CP) and dual-Linear Polarization (LP), depending on the geometry of the radiators.

Applications for electronically steered arrays (ESA) in army communication systems span frequencies from UHF to Ka bands and requirements that include single and multiple beams, various scanning speeds, and different polarizations. The radiating apertures can be planar, conformal or segmented and distributed over multi-faceted structures. Examples include distributed apertures on military vehicles, antennas on elevated posts or towers on stationary or mobile platforms, and others. The beam former is an essential part of the ESA design and its optimization in functionality and cost lead to improving the whole system. This paper presents a concept for a distributed beam former that is composed of two stages: an RF stage with limited scanning steps and a digital stage that is capable of steering multiple beams in all required directions. The two-stage beam former uses fewer A/D converters than its all-digital counterpart and lower losses than the all-RF beam former. Examples are given for multi-faceted apertures., See also ADM002075., The original document contains color images. Presented at the Army Science Conference (25th) held in Orlando, FL on 27-30 November 2006.

Human populations inhabiting urban landscapes have increased from 224 million in 1900 to 2.9 billion in 1999. The wildlife biology profession utilizes telemetry derived location information for ecological and management studies that involve movement, behavior, habitat use, survival, productivity, and others. World-wide there were more than 1.2 billion cellular telephone users in 2003. A cellular phone based telemetry system is a feasible technology to assist wildlife biologists and researchers overcome the obstacles and requirements for conducting research in urbanized landscapes. A study was performed to assess functional and economic feasibility of developing a cellular-based telemetry system for urban wildlife use. A review of current literature that used traditional wildlife telemetry technologies resulted in the focus of four areas: the study of urban wildlife; traditional telemetry technologies; radio tag weights, frequency use, power, and cost of traditional telemetry technologies; and performance of traditional technologies in urban and non-urban landscapes. Geolocation by wireless communications systems is a relatively new market in the United States, and thus requirements and standards are still developing. Due to constraints outlined in this paper, at this time, the most feasible and promising approach to utilizing the cellular infrastructure for geolocation of urban wildlife is by establishing an ad hoc system for data transferal and accomplishing geolocation by ultra-wide band (UWB) technology.

Broadband multiple beam electronically scanned antennas are a key component of the Future Combat Systems. where heavy armor is traded in by active protection systems, and various radar and communications capabilities are integrated into a single Multi-Function RF system. Due to their inherent broadband properties. Rotman lenses have received attention in applications. However, these lenses are electrically large structures. making it difficult to be simulated with reasonable accuracy so that a quick design and fabrication can be achieved. In this paper. we present a novel hybrid technique for the analysis of printed lenses that offers tremendous savings in the required computational resources, when compared to the existing general 3D and 2D electromagnetic simulation tools., See also ADM001736, Proceedings for the Army Science Conference (24th) held in Orlando, FL on 29 Nov-2 Dec 2005. The original document contains color images.