Design of DGS-Enabled Simple UWB MIMO Antenna Having Improvement in Isolation for IoT Applications

Abstract

We report a Multiple Input Multiple Output (MIMO) antenna useful for Ultra-wideband (UWB) applications enabled with modifications and defects in ground structure in this paper. The MIMO antenna covers 320 mm2 footprint and exhibits enhanced diversity performance by achieving low Envelop Correlation Coefficient (ECC), Low Cannel Capacity Loss (CLL) and improvement in isolation. Proposed MIMO antenna is implemented from a very compact UWB antenna having overall size of 16 × 10 × 1.6 mm3 which is the smallest microstrip fed UWB antenna to best of our knowledge. The design involves use of hybrid miniaturization and isolation enhancing techniques by exploiting Modified Ground Structure and Defected Ground Structure (MGS and DGS) approaches to achieve impedance matching in UWB range. The MIMO antenna comprises of a ‘T’-like stub added to rectangular slotted ground plane between two microstrip fed radiators to achieve above −20.5 dB isolation. This UWB MIMO antenna covers 3.1 GHz to more than 11 GHz impedance bandwidth. The antenna achieves Diversity Gain above 9.993 and Envelop Correlation Coefficient (ECC) less than 0.0015 indicating high-quality diversity performance. MIMO antenna obtains stable radiation patterns. All these MIMO parameters are found suitable for Internet of Things (IoT) applications.