US Patent 11404783 Electronic device having dual-frequency ultra-wideband antennas

An electronic device may be provided with antennas for receiving signals in first and second ultra-wideband communications bands. The antennas may include a resonating element formed from conductive traces on a dielectric substrate. The substrate may be mounted to an underlying flexible printed circuit. A fence of conductive vias may extend from the resonating element, through the substrate and the flexible printed circuit, to a ground plane on the flexible printed circuit. The fence may form a return path for the antenna. A shielding ring may be formed on the substrate. Additional fences of vias may couple the shielding ring to the ground plane. If desired, the resonating element may include a patch that is not shorted to the ground plane. The fences of vias, the conductive traces, and the ground plane may form a continuous antenna cavity for the resonating element.