Design, fabrication and testing of pyramidal horn antenna

Horn antennas are widely used in areas of wireless communications, electromagnetic sensing, nondestructive testing and evaluation, radio frequency heating and biomedicine. They are also widely used as high gain elements in phased arrays and as feed elements for reflectors and lens antennas in satellite, microwave and millimeter wave systems. Moreover, they serve as a universal standard for calibration and gain measurements of other antennas.An optimum pyramidal horn with gain 20dB and center frequency 9.5GHz is designed. Using the design values two horn antennas are fabricated using aluminum sheets of different thickness namely 1mm and 2mm. The performance parameters like gain, directivity, impedance and s parameters are evaluated. The results are discussed

A Review on Geopolymer RCC Beams made with Recycled Coarse Aggregate

In present day scenario, concrete construction is rapidly increasing for different uses and aspects irrespective of the economy and its usage. Due to this imbalanced usage of economy, scarcity of raw materials increasing day by day and environment is getting affected due to manufacturing of cement. This study has been done how to reduce environmental pollution by using different kind of bi product materials in replacement to conventional concrete, which is made up of OPC. The cement can be replaced with fly ash; GGBS, rice husk ash etc, aggregates are being partially replaced with recycled aggregates which come from demolished structures and alkaline liquids such as sodium silicates and sodium hydroxide can be used in concrete, which is called geopolymer concrete. Literature review has been carried out to find the optimum content of aggregates to be replaced and the flexure behavior of the beams is being evaluated. From the literature study, it has been identified that the optimum compressive strength is achieved at 30% replacement of recycled aggregate and ductility natures of both Geopolymer and conventional concrete beams are almost similar