A new method for calculating the resonant frequency of electrically thin and thick rectangular microstrip antennas, based on the fuzzy inference systems, is presented. The optimum design parameters of the fuzzy inference systems are determined by using the classical, modified, and improved tabu search algorithms. The calculated resonant frequency results are in very good agreement with the experimental results reported elsewhere. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 108–119, 2000.

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Backscatter communication (BSC) is a promising solution for Internet-of-Things (IoT) connections due to its lowcomplexity, low-cost, and energy-efficient solution for sensors. There are several network infrastructure setups that can be used for BSC with IoT nodes/passive devices. One of them is a bistatic setup where there is a need for high dynamic range and high-resolution analog-to-digital converters at the reader side. In this paper, we investigate a bistatic BSC setup with multiple antennas. We propose a novel algorithm to suppress direct link interference between the carrier emitter (CE) and the reader using beamforming into the nullspace of the CEreader direct link to decrease the dynamic range of the system and increase the detection performance of the backscatter device (BSD). Further, we derive a Neyman-Pearson (NP) test and an exact closed-form expression for its performance in the detection of the BSD. Finally, simulation results show that the dynamic range of the system is significantly decreased and the detection performance of the BSD is increased by the proposed algorithm compared to a system not using beamforming in the CE, which could then be used in a host of different practical fields such as agriculture, transportation, factories, hospitals, smart cities, and smart homes.

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A new, very simple curve-fitting expression for the effective side length is presented for the resonant frequency of triangular microstrip antennas. It is obtained using () a modified tabu search algorithm, and is useful for the computer-aided design CAD of microstrip antennas. The theoretical resonant frequency results obtained using this new effective side length expression are in very good agreement with the experimental results available in the literature.

The article reports on the results of the first ever scientific investigation of all heliographic and heliogravure plates created by Joseph Nicephore Niépce in France that he brought with him in 1827 to England. In hopes of presenting his invention to the Royal Society of London and to the Royal court, he may have selected the best examples of his experiments that were able to demonstrate the entire range of applications of his photographic processes. The in-depth scientific investigation of four still surviving plates in the Royal Photographic Society collection of the National Media Museum in Bradford and the Harry Ransom Center at the University of Texas at Austin provided new insight into the material aspects of J.N. Niépce's experiments, new and sometimes surprising and unexpected information of the image structure and image formation. The microscopic and analytical investigation of the images in combination with a broad battery of supporting analyses, artificial ageing studies and process re-creations allowed us to correct many pieces of information previously obtained by interpreting J.N. Niépce's letters and documents. Our investigation also established, for the first time, a scientifically based conservation baseline for the long term monitoring of the state of preservation of these iconic plates and resulted in the development of new, inert, gas filled and sensor equipped enclosures for their long term display and storage.