Usually microstrip patch antennas radiate at the broadside direction. Instead of the broadside direction, if a patch antenna radiates in a different direction in a controlled way, it may open a novel way of antenna array miniaturisation. For conventional patch antennas, higher order resonance modes are usually considered entirely useless due to the splitting of the maximum radiated power. In this work, a generic process of modifying the higher order natural resonance mode has been proposed by using metamaterial. Owing to this modification, maximum radiation in a particular direction has been achieved while the gain of the side lobe has been decreased at a great instinct. Furthermore, the main lobe is far shifted than the conventional broadside direction. Interestingly, the proposed dual band antenna radiates in two different directions in two different radiating bands, which can be very useful for the possible miniaturisation of printed antenna array.

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In this paper, a novel design for metamaterial loaded rectangular microstrip antenna array has been proposed using hybrid feed combination. Metamaterial has been used as the substrate for single antenna to reduce its dimension and achieve dual band properties, while the hybrid combination of coaxial and microstrip feed has been used to accelerate the reduction of antenna array dimension. Moreover, with the help of metamaterial, dual-band operation with two different radiation pattern has also been achieved. To justify and analyze the performance of this novel design, different designs for 2 elements and 4 elements arrays have been proposed in this paper. In both arrays, the antennas and feeding network have been placed in two different layers. Unlike conventional array design, the feeding network has been designed using microstrip feed lines while coaxial feed cables have been used to connect the antennas to the feeding network. These designs successfully achieved almost 3 dB increase in the gain compared to the single element antenna. The arrays also provided smaller beamwidth and lower side lobe level.