Compact MIMO antenna for UWB application

A 26mm×40mm compact size MIMO (Multiple Input Multiple Output) for Ultrawide band applications is designed. The antenna elements are placed perpendicularly to each other to achieve good isolation. The antenna consists of two monopole antenna elements printed on one side of Roger substrate of 0.8mm thickness. Partial ground is used for the two monopoles which is connected by a short ground strip to form a common ground. Two long ground stubs are added with ground planes to increase the bandwidth and enhance isolation. To study the antenna performance in terms of reflection coefficients simulation and measurement are performed, thus mutual coupling, radiation pattern, realized peak gain, efficiency and envelope correlation coefficient for pattern diversity are studied. Results show that the MIMO antenna has an impedance bandwidth of larger than 3.1-10.6 GHz, low mutual coupling of less than 15 dB, and a low envelope correlation coefficient of less than 0.2 across the frequency band.