Directive Multiband Antenna Based on Rectangular Loop Array and Dumbbell-Shaped Slot Radiator. - Jose Alfredo Tirado-Mendez; Hildeberto Jardon-Aguilar; Ruben Flores-Leal; Luis Alberto Vasquez-Toledo; Arturo Rangel-Merino; Rricardo Marcelin-Jimenez; Enrique Rodríguez-Colina; Michael Pascoe-Chalke (Sensors, 2021)