A body sensor node system-on-chip (SoC) is designed and implemented. The SoC integrates analog front end (AFE), a high-resolution analog-to-digital converter (ADC), an RF-to-DC rectifier, a low dropout (LDO) regulator, and a digital signal processing (DSP) block. The batteryless SoC is powered by RF of 2.45GHz. The rectifier generates 1.8V output and the LDO converts the voltage to stable 1.6V supply for AFE, ADC, and DSP blocks. A pseudo-resistor with huge resistance is used in AFE to support tunable low cut-off frequency and to facilitate compact SoC integration. The DSP can be set to deliver raw data, wavelet-domain data, and compressed-sensing (CS) data. The entire SoC is 1.7×2.5 mm2 and can support invasive/non-invasive health-monitoring with low power consumption.