Spiral resonator for ultra wide band chipless RFID tag

The chipless resonator tags are at the forefront of the conventional barcode replacement research. The tag is still larger in dimension and a matter of concern for the researchers. The resonator tag comprised with two separate antennas working as Tx and Rx, one transmission line and resonators. The resonators have various types of shapes. Recently one rectangular resonator tag is proposed for UWB RFID detection. Here one study is performed to compare the rectangular spiral with the circular spiral to see the effect in terms of space reduction. One rectangular spiral and one circular spiral at the same resonance frequency (2.5GHz) are designed in CST MWS. The result shows a reduction in area of 9.8% while using circular resonator instead of rectangular resonator but with the cost of wideness of the bandwidth

Integrated si lens antenna with planar log-spiral feed for THz band

A hybrid antenna is used to design a mixer in the heterodyne receiver for THz range application to increase the system efficiency. Design of a high precision THz range antenna for a constant far-field beam pattern is always a challenging task to the design engineers. A design procedure of THz band antenna by using CST Microwave Studio has been presented. The antenna has been designed and optimized to achieve constant far field beam as well as fixed polarization. Beam patterns, maximum directivity, on band directivity flatness, polarization, Φ = 0 0 and Φ = 90 0 beam symmetries have been studied for 5mm hemispherical lenses over WR-1.5 band (500GHz to 750GHz). Experimental results show a better matching accuracy within the design considerations

A compact bandpass filter using microstrip hairpin resonator for WLAN applications

This work represents a microstrip hairpin resonator-based bandpass filter for Wireless Local Area Network (WLAN). Two short-circuited microstrip comb-lines have been coupled at the two sides of a rectangular-loop to construct the hairpin resonator. The Taconic TLX-8 material has been used as the substrate to design the filter at a center frequency of 2.45 GHz. The designed filter exhibits a two-pole Chebyshev response with an insertion loss of -0.37 dB and a minimum return loss of -34.03 dB. This compact filter has a fractional bandwidth of 4.37% which sharply selects the entire bandwidth of WLAN frequencies

Win-win: designing dual-use in climate projects for effective anti-corruption in Bangladesh

Climate adaptation projects in Bangladesh have been widely affected by high levels of corruption and resource leakage. However, the dual-use characteristics of climate adaptation investments create incentives for influential households to monitor projects in their own interest. We theorize that these households can effectively use informal power and networks to constrain corruption by contractors and officials. Increasing the level of dual-use benefits is therefore a viable way of reducing corruption in contexts of poor governance. We test this hypothesis using data from a survey of 1,901 households living near four recently completed climate projects and interviews with over 30 key informants. The results indicate that households are more likely to monitor climate projects if they provide dual-use benefits and households with above-average incomes from agricultural and business activities are the most likely to benefit from dual-use attributes. Furthermore, we find that higher levels of monitoring by these influential households are associated with reduced corruption during project implementation

Anaerobic membrane bioreactors for biohydrogen production: recent developments, challenges and perspectives

Biohydrogen as one of the most appealing energy vector for the future represents attractive avenue in alternative energy research. Recently, variety of biohydrogen production pathways has been suggested to improve the key features of the process. Nevertheless, researches are still needed to overcome remaining barriers to practical applications such as low yields and production rates. Considering practicality aspects, this review emphasized on anaerobic membrane bioreactors (AnMBRs) for biological hydrogen production. Recent advances and emerging issues associated with biohydrogen generation in AnMBR technology are critically discussed. Several techniques are highlighted that are aimed at overcoming these barriers. Moreover, environmental and economical potentials along with future research perspectives are addressed to drive biohydrogen technology towards practicality and economical-feasibility

Linear microstrip resonator for UWB RFID tag

The data storage capacity is directly proportional to the number of bits on board of the tag. The main challenge in UWB tag development is to maintain higher number of bits while keeping the tag within the standard size. Higher number of bits also ensures more security and anti-tempering protection of the tagging. In addition, reducing the dimensions of the tag can lead to the possibilities of fully replacing the existing barcode identification system. A new type of planar shorted parallel coupled line microstrip resonator which can replace the existing planar rectangular type resonator has been proposed in this paper. The theoretical approximation and simulation have been performed. A 20-bit resonator has been designed and developed that works between 4.6GHz and 8.1GHz. It is found that the bit density per unit area (cm2) is about 6.67 bit/cm2 has been achieved. The simulation has been performed by CST MWS 2017. The results would motivate the researchers to develop a higher bit density UWB passive RFID tag

A wideband millimeter-wave printable antenna on flexible substrate for breast cancer imaging

Breast cancer is the most diagnosed cancer among women all over the world after skin cancer. Meanwhile, electromagnetic imaging has been a prominent detection technique for biomedical diagnosis in recent years. However, the electromagnetic imaging is struggling with the spatial resolution that can be solved by an imaging technique based on the antenna with a wide operating bandwidth at the higher frequency range. In this paper, a printable Coplanar Waveguide (CPW)-fed microstrip rectangular patch antenna with a wide – 10 dB bandwidth of 18.7 GHz has been proposed for a breast cancer imaging application. This printable antenna, after being designed on a flexible substrate and simulated, operates from 21 GHz to 39.7 GHz which covers the millimeter-wave frequencies. The antenna has achieved an average gain of 4 dBi with an average radiation efficiency of over 80% for the entire -10 dB bandwidth. The bidirectional radiation pattern of the antenna offers the freedom of placing the antenna both at the front and back position on the body surface. Moreover, a compact area of 5×5 mm2 makes the antenna suitable for the biomedical imaging application at mm-wave frequencies by utilizing a low-cost manufacturing process