https://bluemartinpress.com/ojs/index.php/jhct <p><strong>Journal of High-Frequency Communication Technologies (EISSN:2836-9009)</strong> offers a platform for disseminating original and significant research and development activities directed towards the increasingly significant field of communication technology at microwave, millimetre wave and Terahertz frequencies. The journal is available for researchers to publish and read articles that are available to all for free of cost. Research contributions are invited from global academic institutions and organisations.</p> BLUE MARTIN PRESS LLC en-US Journal of High-Frequency Communication Technologies 2836-9009 <p>Articles publishsed in this journal are licensed under a Creative Commons Attribution 4.0 License(CC BY 4.0).<br />For more information, see https://creativecommons.org/licenses/by/4.0/</p> https://bluemartinpress.com/ojs/index.php/jhct/article/view/45 <p>The compressor is the heart of the refrigeration system, extension of its life and preservation of its moving parts such as pistons, rotors, valves, connecting rods and cranks lubrication require improvement. Recently the studies focus on the use nanoparticles with lubricants in refrigeration and air conditioning systems in view of their significant impact on improving the coefficient of performance of these systems as well as thermophysical properties of pure lubricating oils and thus reducing energy consumption. In this study, nanoparticles were synthesized in an easy and cheap way and from materials available in chemistry laboratories as following copper oxide, cerium oxide, mixture 1 consisted of 50% copper oxide with 50% cerium oxide, mixture 2 consisted of 60% copper oxide with 40% cerium oxide, mixture 3 consisted of 70% copper oxide with 30% cerium oxide, mixture 4 consisted of 40% copper oxide with 60% cerium oxide, and mixture 5 consisted of 30% copper oxide with 70% cerium oxide to study their effectiveness on enhancing the thermophysical properties of POE, PAG lubricating oil using mathematical equations available from earlier studies. The results obtained from the mathematical equations showed an increase in the viscosity of POE from 40 mm2/sec to 45 mm2/sec at 0.05 wt.% and reached 108.86 mm2/sec by increasing the concentration of nanoparticles to 0.33wt.%, as well as the improvement of viscosity of PAG from 46 mm2/sec to 52.9 mm2/sec at the concentration of nanoparticles 0.05 wt.%, recording a significant improvement when the concentration of nanoparticles reached 0.33 wt.%, as well as for the rest of the other physical properties. This is consistent with earlier studies that confirmed the improvement of the physical properties of lubricants through mixing them with nanoparticles.</p> HudaElslam Mohamed Ali A. Salama Abdussalam Ali. Ahmed Unal Camdali Copyright (c) 2024 HudaElslam Mohamed, Ali A. Salama, Abdussalam Ali. Ahamed, Unal Camdali https://creativecommons.org/licenses/by/4.0 2024-11-12 2024-11-12 2 04 201 214 10.58399/FHSN6736 https://bluemartinpress.com/ojs/index.php/jhct/article/view/52 <p>High-performance RF transceiver systems create large demands in multimode wireless communication system applications with high-frequency suppression, increased spectral utilization, and flexibility to control stopband and passband frequency characteristics. This review analyzes microstrip bandstop filters mentioned in from recent research articles focusing on their performance characteristics, design techniques and applications. Filters are categorized into five categories, namely, Single stopband bandstop filter, Dual stopband BSF, Wide stopband BSFs, Low pass with Wide stopband BSFs, and reconfigurable filters, this article deals with a study of these filters. An extensive analysis of the filter design techniques including the type of resonators, coupled line sections, open/short-circuited stubs, DGS/DMS, and flexible switching devices has been made with comparison and exploration of the simulated, measured frequency responses in each category.</p> Selvakumar Arumugam Kanaparthi V. Phani Kumar Rusan Kumar Barik Copyright (c) 2024 Selvakumar Arumugam, Kanaparthi V. Phani Kumar, Rusan Kumar Barik https://creativecommons.org/licenses/by/4.0 2024-11-30 2024-11-30 2 04 215 237 10.58399/TNUG3825