This invention provides conformal antenna structures, how to make and use the antenna structures, and systems in which the antenna structures may be used for biometric sensing of humans and other animals. The antenna structures of the invention includes at least one relatively flexible section connecting relatively rigid sections. The relatively flexible section connecting relatively rigid sections may flex so that the relatively rigid sections connected to the relatively flexible section can change orientation relative to one another. This allows the relatively rigid sections to be conformed to a region of a surface of a human or animal that is not flat (that is curved).