A Low Mutual Coupling Circle Microstrip Array Antenna for 5.8 GHz Band

Abstract

In order to effectively suppress the influence of mutual coupling between array elements on antenna radiation performance, a novel dual-circle microstrip patch array antenna with low mutual coupling and low correlation is proposed. Two deformed E-shaped electromagnetic bang gap (EBG) structures are symmetrically inserted between two circular antenna elements, which could suppress the surface waves propagation to reduce the mutual coupling through theoretical analysis and experimental verification. In addition, several arc-shaped gap defected ground structures (DGS) are symmetrically etched on the ground plane to curb the ground coupling current, thus, the mutual coupling is further decreased. The shortest distance between the two circular antenna elements is only 0.19λ where λ is the wavelength at the working frequency of 5.8 GHz. Both the simulated and experimental results indicate that the mutual coupling of less than -40 dB and the envelope correlation coefficient (ECC) value of less than 0.001 can be achieved by the proposed decoupling antenna within its operating bandwidth, to make the good decoupling effect under the premise of small antenna size and stable radiation performance.

Keywords

• |array antenna|microstrip patch|low mutual coupling|low correlation|electromagnetic band gap (ebg) structures|defected ground structures (dgs)