A triple-slotted substrate integrated cavity-fed 2 x 2 metasurface antenna with wide bandwidth

This article presents a triple-slotted substrate integrated cavity (SIC)-fed 2 x 2 metasurface antenna. Three modes can be obtained including TM10 mode of the metasurface, TE210, mode and TE310 mode of the SIC. The TE210 mode of SIC radiates through the two side slots and is coupled to the metasurface mainly by the two side slots, while the TE310 mode of SIC is mainly coupled to the metasurface by the middle slot. Comparing with the reported SIC-backed slot antenna, dual-slotted SIC-fed patch antenna or the metasurface antenna, the proposed antenna exhibits the advantage of wide bandwidth with flat gain. One prototype operated at 10 GHz was fabricated and measured with 10-dB fractional bandwidth of 33%, the gain of 8.1 dBi at the center frequency, the cross polarization level of 20 dB and the gain ripple of 1.5 dB.