Study on isolation improvement between closely‐packed patch antenna arrays based on fractal metamaterial electromagnetic bandgap structures

A decoupling metamaterial (MTM) configuration based on fractal electromagnetic-bandgap (EMBG) structure is shown to significantly enhance isolation between transmitting and receiving antenna elements in a closely-packed patch antenna array. The MTM-EMBG structure is cross-shaped assembly with fractal-shaped slots etched in each arm of the cross. The fractals are composed of four interconnected-`Y-shaped' slots that are separated with an inverted-`T-shaped' slot. The MTM-EMBG structure is placed between the individual patch antennas in a 2 × 2 antenna array. Measured results show the average inter-element isolation improvement in the frequency band of interest is 17, 37 and 17 dB between radiation elements #1 & #2, #1 & #3, and #1 & #4, respectively. With the proposed method there is no need for using metallic-via-holes. The proposed array covers the frequency range of 8-9.25 GHz for X-band applications, which corresponds to a fractional-bandwidth of 14.5%. With the proposed method the edge-to-edge gap between adjacent antenna elements can be reduced to 0.5λ 0 with no degradation in the antenna array's radiation gain pattern. Across the array's operating band, the measured gain varies between 4 and 7 dBi, and the radiation efficiency varies from 74.22 and 88.71%. The proposed method is applicable in the implementation of closely-packed patch antenna arrays used in SAR and MIMO systems.

[1]  P. Padilla,et al.  New EBG solutions for mutual coupling reduction , 2012, 2012 6th European Conference on Antennas and Propagation (EUCAP).

[2]  Qian Xu,et al.  Reduction of mutual coupling between closely-packed antenna elements using defected ground structure , 2009, 2009 3rd IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications.

[3]  T. Cui,et al.  Reduction of Mutual Coupling Between Closely Packed Patch Antennas Using Waveguided Metamaterials , 2012, IEEE Antennas and Wireless Propagation Letters.

[4]  M. Islam,et al.  COMPACT EBG STRUCTURE FOR ALLEVIATING MUTUAL COUPLING BETWEEN PATCH ANTENNA ARRAY ELEMENTS , 2013 .

[5]  D. Schreurs,et al.  Mutual Coupling Reduction Between Planar Antennas by Using a Simple Microstrip U-Section , 2012, IEEE Antennas and Wireless Propagation Letters.

[6]  Susanta Kumar Parui,et al.  Reduction of mutual coupling between E-shaped microstrip antennas by using a simple microstrip I-section , 2013 .

[7]  Tzu-Chun Tang,et al.  An Ultrawideband MIMO Antenna With Dual Band-Notched Function , 2014, IEEE Antennas and Wireless Propagation Letters.

[8]  H. S. Farahani,et al.  Mutual Coupling Reduction in Patch Antenna Arrays Using a UC-EBG Superstrate , 2010, IEEE Antennas and Wireless Propagation Letters.

[9]  Y. Rahmat-Samii,et al.  Microstrip antennas integrated with electromagnetic band-gap (EBG) structures: a low mutual coupling design for array applications , 2003 .

[10]  Mitchai Chongcheawchamnan,et al.  Mutual Coupling Reduction for High-Performance Densely Packed Patch Antenna Arrays on Finite Substrate , 2016, IEEE Transactions on Antennas and Propagation.

[11]  P. Padilla,et al.  Mutual Coupling Reduction Using EBG in Steering Antennas , 2012, IEEE Antennas and Wireless Propagation Letters.

[12]  O. Quevedo-Teruel,et al.  Mutual Coupling Reduction in Patch Antenna Arrays by Using a Planar EBG Structure and a Multilayer Dielectric Substrate , 2008, IEEE Transactions on Antennas and Propagation.

[13]  M. Kanagasabai,et al.  Implementation of Slotted Meander-Line Resonators for Isolation Enhancement in Microstrip Patch Antenna Arrays , 2013, IEEE Antennas and Wireless Propagation Letters.

[14]  Omar M Ramahi,et al.  Mutual Coupling Reduction Between Microstrip Patch Antennas Using Slotted-Complementary Split-Ring Resonators , 2010, IEEE Antennas and Wireless Propagation Letters.

[15]  R. Janaswamy.  Effect of element mutual coupling on the capacity of fixed length linear arrays , 2002, IEEE Antennas and Wireless Propagation Letters.

[16]  Z. Qamar,et al.  Compact Waveguided Metamaterials for Suppression of Mutual Coupling in Microstrip Array , 2014 .

[17]  Jaume Anguera,et al.  The fractal Hilbert monopole: A two‐dimensional wire , 2003 .

[18]  Ning Wang,et al.  A Wide Band-Gap Slot Fractal UC-EBG Based on Moore Space-Filling Geometry for Microwave Application , 2017, IEEE Antennas and Wireless Propagation Letters.

[19]  M. F. Shafique,et al.  Coupling suppression in densely packed microstrip arrays using metamaterial structure , 2015 .

[20]  Jing-Song Hong,et al.  Isolation Enhancement of a Very Compact UWB-MIMO Slot Antenna With Two Defected Ground Structures , 2015, IEEE Antennas and Wireless Propagation Letters.

[21]  Sekhar Ranjan Bhadra Chaudhuri,et al.  Mutual Coupling Reduction Between Closely Placed Microstrip Patch Antenna Using Meander Line Resonator , 2016 .

[22]  D. R. Poddar,et al.  UWB monopole antenna with multiple fractal slots for band-notch characteristic and integrated Bluetooth functionality , 2015 .

[23]  Ang Yu,et al.  A novel method to improve the performance of microstrip antenna arrays using a dumbbell EBG structure , 2003, IEEE Antennas and Wireless Propagation Letters.

[24]  J. Nourinia,et al.  A rectangular defected ground structure (DGS) for reduction of mutual coupling between closely-spaced microstrip antennas , 2012, 20th Iranian Conference on Electrical Engineering (ICEE2012).

[25]  J. Ouyang,et al.  Reducing Mutual Coupling of Closely Spaced Microstrip MIMO Antennas for WLAN Application , 2011, IEEE Antennas and Wireless Propagation Letters.

[26]  Ying Liu,et al.  Isolation Enhancement in Patch Antenna Array With Fractal UC-EBG Structure and Cross Slot , 2017, IEEE Antennas and Wireless Propagation Letters.

[27]  Tayeb A. Denidni,et al.  Millimeter-Wave Compact EBG Structure for Mutual Coupling Reduction Applications , 2015, IEEE Transactions on Antennas and Propagation.

[28]  A. Ludwig.  Mutual coupling, gain and directivity of an array of two identical antennas , 1976 .