Low-Profile Patch Antenna Pair With Pattern Diversity Using Common and Differential Modes for MIMO Systems

Abstract

We propose a low-profile hexagonal patch antenna pair with pattern diversity by using a single shared radiator. More specifically, both equivalent circuit and full wave simulation results show that the common mode and the differential mode of the grounded hexagonal patch could be excited with similar resonant frequencies, and then the coupling-feed method is employed to extend the impedance bandwidth. Simulation and measurement results demonstrate that such antenna pair, featuring a better decoupling performance, could be capable of generating both of the apple-shaped radiation pattern and the broadside radiation pattern in a wide band with the shared patch size of 0.2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \lambda _{0}$</tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \times\, 0.37\, \lambda _{0}$</tex-math></inline-formula> and the profile height of 0.05 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \lambda _{0}$</tex-math></inline-formula> . The proposed design should pave the way for the development of more compact multiple-input–multiple-output (MIMO) systems.