A dual-beam microstrip array antenna based on conical beam elements is proposed in this paper. Circular patch operating at the TM01 mode is used to achieve conical beam pattern. Grating lobes of the array is used to obtain dual-beam patterns with large elevation angle and high gain. Detailed analysis and design have been presented. A 4x4 antenna prototype has been fabricated and measured. Experimental results show that the antenna array has the return loss better than 10 dB over 12.26 GHz-12.88 GHz and exhibits two symmetric radiation beams, directed at ±49.4° with 16.6 dBi gain at 12.5 GHz. Good agreement between the simulated and measured results is observed. Compared with the previous scheme, the alternative proposal possesses the advantages of being easy to form a planar array with low cross-polarization and having relatively high aperture efficiency simultaneously.
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