This paper considers a dual-hop cooperative satellite-unmanned aerial vehicle (UAV) communication system including satellite (S) and group of cluster headers (CHs) which are respectively with uniformly distributed UAVs. Specifically, the CHs serve as decode-and-forward relays to forward information transmitted by S Moreover, free-space optical (FSO) radio frequency (RF) technologies adopted ove...

This paper presents a novel design of compact contra-directional coupler with high directivity for high-power monitoring in frequency. Microstrip parallel coupled lines are widely used directional couplers; however, they show poor inherently. Their has been improved by many works. However, the suggested approaches often result other limitations, such as weak structure monitoring, or larger size...