This paper introduces a high-resolution dielectric sensor at 162GHz. The proposed system consists of a fundamental oscillator as the transmitter, a ring resonator based dielectric sensor, and a low noise super-regenerative receiver. A sinusoidal tone, generated by the transmitter, passes through the sensor and gets different attenuation due to the resonant frequency shift resulting from materials of different dielectric constants. The super-regenerative receiver then detects the resulting small signal difference caused by different dielectric constants to complete the sensing operation. The active transmitter and receiver are fabricated in CMOS technologies. Thanks to the ring resonator's high sensitivity and receiver's ultra-low noise, the sensor can achieve the best dielectric constant sensing resolution of 3.10×10-4 at the frequency range above 100GHz. The sensing system consumes total of 9mW DC power.