A system (100, 200, 300, 400) comprising: a plurality of devices (102, 304, 306, 308, 404, 406, 408, 410, 412, 414), for electromagnetic structural characterization, wherein each device is configured to be positioned proximate to a biological structure, and wherein each device comprises: an antenna system having a first antenna and a second antenna; and a controller having: an electromagnetic transmitter output; an electromagnetic receiver input, and a communications interface; wherein the controller of each device is configured to: send a signal over the electromagnetic transmitter output that causes the antenna system of that device, which is configured to be located at a first location proximate to the biological structure, to generate a first electrical field, E1, and a first magnetic field, H1; receive, over the communications interface, a second electric field, E2, and a second magnetic field, H2, received by the antenna system of that device, wherein said second electric field, E2, and said second magnetic field, H2 result from the interaction of said first electrical field, E1, and said first magnetic field, H1 emitted by another device of said plurality of devices towards the structure to be characterized, wherein said other device is configured to be located at a second location proximate to the biological structure, wherein the first electrical field, E1, the first magnetic field, H1, the second electric field, E2, and the second magnetic field, H2, are near field electromagnetic induction fields; and calculate an impedance based on the second electric field, E2, and the second magnetic field, H2, interacting with the biological structure, and wherein each device is further operable to cause the antenna system of that device to generate a said first electrical field, E1, and a said first magnetic field, H1, for data communications with said other device based on a defined communication protocol. an antenna system having a first antenna and a second antenna; and a controller having: an electromagnetic transmitter output; an electromagnetic receiver input, and a communications interface; an electromagnetic transmitter output; an electromagnetic receiver input, and a communications interface; wherein the controller of each device is configured to: send a signal over the electromagnetic transmitter output that causes the antenna system of that device, which is configured to be located at a first location proximate to the biological structure, to generate a first electrical field, E1, and a first magnetic field, H1; receive, over the communications interface, a second electric field, E2, and a second magnetic field, H2, received by the antenna system of that device, wherein said second electric field, E2, and said second magnetic field, H2 result from the interaction of said first electrical field, E1, and said first magnetic field, H1 emitted by another device of said plurality of devices towards the structure to be characterized, wherein said other device is configured to be located at a second location proximate to the biological structure, wherein the first electrical field, E1, the first magnetic field, H1, the second electric field, E2, and the second magnetic field, H2, are near field electromagnetic induction fields; and calculate an impedance based on the second electric field, E2, and the second magnetic field, H2, interacting with the biological structure, and send a signal over the electromagnetic transmitter output that causes the antenna system of that device, which is configured to be located at a first location proximate to the biological structure, to generate a first electrical field, E1, and a first magnetic field, H1; receive, over the communications interface, a second electric field, E2, and a second magnetic field, H2, received by the antenna system of that device, wherein said second electric field, E2, and said second magnetic field, H2 result from the interaction of said first electrical field, E1, and said first magnetic field, H1 emitted by another device of said plurality of devices towards the structure to be characterized, wherein said other device is configured to be located at a second location proximate to the biological structure, wherein the first electrical field, E1, the first magnetic field, H1, the second electric field, E2, and the second magnetic field, H2, are near field electromagnetic induction fields; and calculate an impedance based on the second electric field, E2, and the second magnetic field, H2, interacting with the biological structure, and wherein each device is further operable to cause the antenna system of that device to generate a said first electrical field, E1, and a said first magnetic field, H1, for data communications with said other device based on a defined communication protocol.