In this paper, an interdigital resonator that can greatly decrease mutual coupling between adjacent patches is proposed to realize an ultra-compact microstrip antenna array operating in 2.4 GHz wireless communication system. Due to its remarkable performance of decoupling, the edge to edge distance between adjacent patches can be reduced to 0.08λ0 and even less. Meanwhile, a miniaturized feeding network, which is composed of a CRLH-TL-based phase shifter and T-junction-based power divider, is used to feedthe compact antenna array. The simulation results show that the proposed antenna array has an impedance bandwidth of 8.34%. We fabricate the antenna array to verify its performance. The experimental results are in good agreements with the simulations. Compared to the published designs, the proposed antenna array hasanultra-compact structure and hence can be used in space limited communication systems.
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