A 26 GHz retro-reflective array for long-range RFID applications
A unique design of series-fed grounded coplanar waveguide (GCPW) patch arrays for use in retro-reflective arrays is presented. For the current application, a planar retro-reflector which is capable of providing large radar cross-section (RCS) and signal modulation, and can also operate on metallic surfaces from 25.5–26.5GHz is desired. Linear, series-fed GCPW patch arrays are employed as the radiating elements. Using constituent arrays allows maximization of RCS using the minimum number of active components. Additionally, the unique orientation of the series-fed arrays provides beam squinting, allowing for ease of target identification and distinguishing the response from that of the array ground plane. The array design and results are briefly presented herein. Integration of the array in the intended system application is discussed in a separate conference submission.
Closed-Loop Feed Architectures for RCS Beam Broadening of Retro-Reflective Arrays
This communication presents a novel architecture for a one-dimensional, large radar cross section (RCS) retro-reflective array. This array is tailored to aide in the standoff detection and localization of large metallic objects in a warehouse setting. This application scenario requires this retro-reflective array to be planar, provide a high RCS, and a wide beam in the elevation plane. Traditional methods to increase the RCS of planar arrays employ an increase in the number of array elements which typically results in a narrowing of the beam in this plane. The approach presented eliminates this problem. To maintain a wider beam in elevation, a unique series fed grounded coplanar waveguide (GCPW) patch element is designed to radiate off boresight at a specified degree. This linear array is fed from both terminal ends of the array through a unique `closed-loop' interconnection scheme. In this arrangement, a resonant structure is created through circular loops that are formed by the interconnection of the linear series arrays and associated feed lines. The result is a broadened beam in elevation when compared to that of traditional Van Atta interconnection schemes while maintaining the broad RCS expected of a retro-reflective array in the horizontal plane. This compact array has a large RCS and is implemented at 26 GHz. The design of the array elements themselves is discussed along with the development of this novel feed architecture. RCS pattern measurements from the fabricated arrays are presented and performance enhancements quantified when compared to traditional retro-reflector feed geometries.
New Trends in Fungal Biooxidation
Biooxidations using isolated biocatalysts for the oxidative conversion of organic compounds and materials are becoming more and more important in the industrial sector. Research in this direction is part of the rapidly developing field of White Biotechnology and is carried out not least against the background of sustainable development and the need to replace environmentally risky technologies by eco-friendly processes. Whereas whole cells are already widely used as oxidative biocatalysts, the application of isolated enzymes is still limited to a few examples. One reason for that is the cost-intensive production and laborious purification of enzymes which are mostly intracellular and sometimes membrane-bound proteins with low stability and complex co-factor requirements. The use of secreted oxidoreductases offers several advantages: they are easier to separate and purify, need only cheap co-substrates such as dioxygen or peroxides and are far more stable than intracellular enzymes. Filamentous fungi secrete a broad spectrum of oxidative biocatalysts which are involved, amongst others, in the degradation of recalcitrant biopolymers, the synthesis of melanins as well as the detoxification of plant ingredients, microbial metabolites and organopollutants. We focus here on novel secreted enzymes - peroxygenases and DyP-type peroxidases - with remarkable catalytic properties. Furthermore selected features of “classic” fungal oxidoreductases, such as laccase, tyrosinase and chloroperoxidase, are discussed against the background of innovative recent developments in the field of enzyme application.