A monolithic humidity sensor design based on a standard complementary metal-oxide-semiconductor(CMOS)process is proposed

which integrates an interdigital capacitive humidity element with polyimide as the humidity-sensitive material and capacitance-to-digital converter(CDC)circuit.The humidity-sensitive capacitance is converted into a voltage and digitized by a third-order Δ-Σ modulator CDC.By leveraging a dual-quantization CDC principle

the proposed sensor enhances the resolution without increasing the number of quantizer bits

thereby achieving high-precision humidity measurement.Experimental results demonstrate that the humidity sensor based on dual-quantization CDC principle achieves 12.5-bit capacitance-to-digital conversion within a measurement time of 0.8ms

with a current consumption as low as 15.48μW.The sensor achieves a resolution of 0.05% RH across the 10% to 90% RH range

a single measurement energy comsumption of 8.3nJ.