A liquid crystal cell in which antenna units are arranged includes a TFT substrate, a slot substrate, and a liquid crystal layer. The TFT substrate includes a first dielectric substrate, TFTs supported by the first dielectric substrate and patch electrodes electrically connected to the TFTs, and a first alignment film covering a groove part between the adjacent patch electrodes. The slot substrate includes a second dielectric substrate, a slot electrode including slots and supported by the second dielectric substrate, and a second alignment film covering the slot electrode. The liquid crystal layer sandwiched between the TFT substrate and the slot substrate. The liquid crystal layer includes a liquid crystal material having a lower limit temperature of a nematic phase of the liquid crystal material of −32° C. or lower and an upper limit temperature of the nematic phase of the liquid crystal material of 110° C. or higher.