A method of non-invasive detection of an analyte includes generating a transmit signal having at least two different frequencies each of which is in a radio or microwave frequency range of the electromagnetic spectrum, and transmitting the transmit signal into a target containing at least one analyte of interest using at least one transmit antenna/element. At least one receive antenna/element that is decoupled from the at least one transmit antenna/element is used to detect a response resulting from transmitting the transmit signal by the at least one transmit antenna/element into the target containing the at least one analyte of interest. In one embodiment, the at least one transmit antenna/element can have a first geometry and the at least one receive antenna/element can have a second geometry that is geometrically different from the first geometry.