Compact Ultra-Wideband Series-Feed Microstrip Antenna Arrays for IoT Communications

Modern communication systems require high bandwidth to meet the needs of the huge number of sensors and the growing amount of data consumed, and an exponential growth is expected in the future with the integration of internet of things networks. Spectrum regions in the millimeter waves have aroused new interests, mainly because of the contiguous bands available to meet these needs. In return, and to combat the high losses of propagation in these frequencies, higher gain antennas are needed. This paper describes the use of a logarithmic architecture in the design of microstrip antenna arrays, creating structures with high gain and ultra-wide bandwidth. Three different solutions are presented with five, seven, and nine elements, reaching about 25%, 30%, and 44% of bandwidth, achieving ultra-wideband behavior, efficient and with a compact structure operating at frequencies in around 28 GHz.