A wearable health monitoring device is disclosed. The device includes an attachment feature configured to engage with an attachment feature of an alignment element that is to be worn on the skin of a person, An RF front-end including a semiconductor substrate, at least one transmit antenna configured to transmit radio waves below the skin surface of the person, and a two-dimensional array of receive antennas configured to receive radio waves, the received radio waves including a reflected portion of the transmitted radio waves, wherein the semiconductor substrate includes circuits configured to generate signals in response to the received radio waves, a digital baseband system configured to generate digital data in response to the signals, wherein the digital data is indicative of a health parameter of the person, and a communications interface configured to transmit the digital data generated by the digital baseband system from the wearable health monitoring device.
