Digital pattern synthesis with a compact MIMO antenna of half-wavelength diameter

Abstract The paper presents a compact multiport antenna, with beamforming capabilities and a realized gain of 4.31 dBi with the size of λ/2. The antenna allows digital beamforming with independent control over three parameters: main-beam direction, beamwidth, and null-depth. Those parameters can be dynamically adjusted within a continuous range, create multiple beams for different frequency channels, and simultaneously generate multiple digital patterns. Due to digital beamforming capabilities, the proposed antenna offers much greater flexibility over switch-based analogue beamforming of Electronically Steerable Parasitic Array Radiator (ESPAR) antennas. The reconfiguration properties are achieved by using superposition of three dipole-like radiation patterns, where each radiator generates different spherical mode, i.e. with different angular phase distribution in the horizontal plane. This allows beamsteering with compact size, while the use of different modes ensures low Envelope Correlation Coefficient (ECC) from 10-4 to 3.2×10-5 for the operating frequency of 2.4 GHz. The proposed technique allows for significantly greater pattern reconfiguration than any reconfigurable antenna or array of comparable size and is a perfect candidate for Software Defined Radios.

[1]  Peter A. Hoeher,et al.  Single-Element Beamforming Using Multi-Mode Antenna Patterns , 2020, IEEE Wireless Communications Letters.

[2]  Ahmed M. Eltawil,et al.  A Beam-Steering Reconfigurable Antenna for WLAN Applications , 2015, IEEE Transactions on Antennas and Propagation.

[3]  Muhammad Ramlee Kamarudin,et al.  Steerable Higher Order Mode Dielectric Resonator Antenna With Parasitic Elements for 5G Applications , 2017, IEEE Access.

[4]  Lukasz Kulas,et al.  Low-Profile ESPAR Antenna for RSS-Based DoA Estimation in IoT Applications , 2019, IEEE Access.

[5]  Ahmed A. Kishk,et al.  Theory of ESPAR Design With Their Implementation in Large Arrays , 2014, IEEE Transactions on Antennas and Propagation.

[6]  Buon Kiong Lau,et al.  Multiplexing Efficiency of MIMO Antennas , 2011, IEEE Antennas and Wireless Propagation Letters.

[7]  Xun Gong,et al.  An Electronically Steerable Parasitic Array Radiator (ESPAR) Using Cavity-Backed Slot Antennas , 2019, IEEE Antennas and Wireless Propagation Letters.

[8]  Zhenghe Feng,et al.  A Hemispherical 3-D Null Steering Antenna for Circular Polarization , 2015, IEEE Antennas and Wireless Propagation Letters.

[10]  Behrouz Babakhani,et al.  Dual Null Steering and Limited Beam Peak Steering Using Triple-Mode Circular Microstrip Patch Antenna , 2017, IEEE Transactions on Antennas and Propagation.

[11]  S. Ebadi,et al.  A Microstrip Patch Electronically Steerable Parasitic Array Radiator (ESPAR) Antenna With Reactance-Tuned Coupling and Maintained Resonance , 2012, IEEE Transactions on Antennas and Propagation.

[12]  Buon Kiong Lau,et al.  Design of Closely Packed Pattern Reconfigurable Antenna Array for MIMO Terminals , 2017, IEEE Transactions on Antennas and Propagation.

[13]  A. Kishk,et al.  $X$ -Band Circularly Polarized Electronically Steerable Parasitic Array Radiator of DRA , 2018, IEEE Transactions on Antennas and Propagation.

[14]  Athanasios G. Kanatas,et al.  Pattern reconfigurable ESPAR antenna for vehicle-to-vehicle communications , 2018 .

[15]  Guanghui Xu,et al.  An Electrically Steerable Parasitic Array Radiator in Package Based on Liquid Crystal , 2019, IEEE Antennas and Wireless Propagation Letters.

[16]  Shry-Sann Liao,et al.  Compact Planar Microstrip Branch-Line Couplers Using the Quasi-Lumped Elements Approach With Nonsymmetrical and Symmetrical T-Shaped Structure , 2006, IEEE Transactions on Microwave Theory and Techniques.

[17]  Mohammad S. Sharawi,et al.  Current Misuses and Future Prospects for Printed Multiple-Input, Multiple-Output Antenna Systems [Wireless Corner] , 2017, IEEE Antennas and Propagation Magazine.

[18]  Max J. Ammann,et al.  Switchless Reconfigurable Antenna With 360° Steering , 2016, IEEE Antennas and Wireless Propagation Letters.

[19]  Per-Simon Kildal,et al.  Correlation and capacity of MIMO systems and mutual coupling, radiation efficiency, and diversity gain of their antennas: simulations and measurements in a reverberation chamber , 2004, IEEE Communications Magazine.

[20]  Fredrik Tufvesson,et al.  Mean effective gain of antennas in a wireless channel , 2009 .

[21]  Long Zhang,et al.  Planar Ultrathin Small Beam-Switching Antenna , 2016, IEEE Transactions on Antennas and Propagation.

[22]  Haitao Liu,et al.  Electrically Small and Low Cost Smart Antenna for Wireless Communication , 2012, IEEE Transactions on Antennas and Propagation.

[23]  Simone Genovesi,et al.  Advantageous Exploitation of Characteristic Modes Analysis for the Design of 3-D Null-Scanning Antennas , 2017, IEEE Transactions on Antennas and Propagation.

[24]  J.T. Bernhard,et al.  Performance Study of Pattern Reconfigurable Antennas in MIMO Communication Systems , 2008, IEEE Transactions on Antennas and Propagation.

[25]  Haitao Liu,et al.  Small Director Array for Low-Profile Smart Antennas Achieving Higher Gain , 2013, IEEE Transactions on Antennas and Propagation.

[26]  Richard W Ziolkowski,et al.  Highly Subwavelength, Superdirective Cylindrical Nanoantenna. , 2018, Physical review letters.

[27]  Seong-Ook Park,et al.  Analysis of Mutual Coupling, Correlations, and TARC in WiBro MIMO Array Antenna , 2007, IEEE Antennas and Wireless Propagation Letters.

[28]  M. Ammann,et al.  Calculating the envelope correlation coefficient directly from spherical modes spectrum , 2017, 2017 11th European Conference on Antennas and Propagation (EUCAP).

[30]  S. Gao,et al.  Compact Smart Antenna With Electronic Beam-Switching and Reconfigurable Polarizations , 2015, IEEE Transactions on Antennas and Propagation.

[31]  Youssef Tawk,et al.  Reconfigurable Antennas: Design and Applications , 2015, Proceedings of the IEEE.

[32]  R. Ziolkowski,et al.  Ultralow-Profile, Electrically Small, Pattern-Reconfigurable Metamaterial-Inspired Huygens Dipole Antenna , 2020, IEEE Transactions on Antennas and Propagation.