Antenna Arrays Estimation and Minimization of the Cramer-Rao lower bound for radio direction-finding on the azimuth and elevation of planar antenna arrays/Open Call Articles MIMO OFDM DOA Estimation Algorithm Implementation and Validation Using SDR Platform/Open Call Articles Performance of a New Design Based on Substrate-Integrated Waveguide Slotted Antenna Arrays for Dual-Band Applications (Ku / K)/Special Issue on Internet of Things: Hardware and Software Solutions