MIMO antenna arrays built on metamaterial substrates

• US 8,836,608 B2
• Filed: 12/01/2009
• Issued: 09/16/2014
• Est. Priority Date: 12/01/2008
• Status: Active Grant

• Current Assignee: Drexel University
• Original Assignee: Drexel University
• Inventors: Dandekar, Kapil R., Mookiah, Prathaban
• Primary Examiner(s): Frech, Karl D
• Application Number:
  US13/131,891
• Publication Number:
  US 20110260946A1
• Time in Patent Office: 1,750 Days
• Field of Search: 343/893, 343/787
• US Class Current: 343/893
• CPC Class Codes: B65D 65/403 with at least one corrugated layer
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 1/526 Electromagnetic shields
• CPC Class Codes: H01Q 15/006 Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: H01Q 9/045 with particular feeding means for circular polarisation H01Q9/0428
• CPC Class Codes: Y10T 29/49004 including measuring or testing of device or component part

Abstract

A magnetic permeability enhanced metamaterial is used to enhance the antenna array of a Multiple Input Multiple Output (MIMO) communication system. A rectangular patch antenna array is formed including a stack of a plurality of unit cells, where each unit cell includes an inductive loop of magnetic permeability enhanced metamaterials embedded in a host dielectric substrate. The use of such metamaterials permits the antenna arrays to be made smaller, and have less mutual coupling, when using a metamaterial substrate. The measured channel capacities of the antenna arrays are similar for the metamaterial and conventional substrates; however, the capacity improvement when using MIMO relative to single antenna communication systems is greater for antennas on metamaterial substrates.

Claims

1. A method of improving the capacity and mutual coupling performance of a MIMO antenna array, comprising:

selecting N_T transmitter antennas and NR receiver antennas each comprising a metamaterial substrate so as to form a resonance structure based on induced inductance of the metamaterial substrates combined with the capacitance of the metamaterial substrates;

determining a statistical description of a transmission environment including said MIMO antenna array, where the statistical description is provided in a matrix H_i, where Hi is the normalized channel matrix corresponding to an i^th channel realization where H_i includes interference and signal to noise as a product of the location and spacing of the N_T transmitter antennas and N_R receiver antennas;

using the normalized channel matrix to compute the channel capacity C for each array configuration for a given subcarrier; and

placing said N_T transmitter antennas and said N_R receiver antennas, mounted on said metamaterial substrates, in an array configuration so that the resulting antenna array has channel capacities C that are approximately the same as channel capacities C of relatively larger antenna arrays formed without said metamaterial substrates.

2. The method of claim 1, wherein computing the channel capacity C of each channel i is computed as: