LOW-COST DIAGNOSTICS: RF DESIGNER’S APPROACH*
Silicon radio frequency (RF) integrated circuits (ICs) have been widely used in modern wireless communication systems in the past few decades. In this chapter, we present a different application of silicon RF IC, that is, sensing biological objects.
In an early stage of disease development, biomolecules characteristic to the disease, such as viruses and cancer marker proteins, emerge. The ability to sense these biomolecules would facilitate early disease detection. Researchers from many areas of science and engineering are developing a variety of biosensors, aiming at increased sensitivity or low-cost diagnostics . Our RF biosensor represents a “circuit designer’s way” to pursue highly sensitive biosensing in a portable form.
Figure 16.1 shows our RF biosensor, central to whose operation is the silicon RF transceiver IC. The underpinning physical phenomenon of our sensing method is nuclear magnetic resonance (NMR), the resonant interaction between RF magnetic fields and protons in water, which is altered by the presence of target biological objects. This NMR-based biosensing was developed in 2002  and has been used within a state-of-the-art commercial benchtop NMR system , which, however, is bulky and heavy (120 kg). The main contribution of our work is to drastically shrink the entire NMR system by developing the RF transceiver IC, hence enabling NMR-based biosensing in ...