This research dissertation reports the development of an RF sensor IC chip capable of tracking the directionality of RF remote emissions. The IC design uses an angle-of-arrival algorithm, and it is designed for the 180 nm CMOS technology, and also applicable to other technologies. The sensor chip requires two pairs of antennas aligned and placed at distance s for detection of azimuthal and polar angles of the RF incident wave. The circuit consists of custom designed low-noise amplifiers (LNAs) at the front-end, with a novel design of double-balanced Gilbert cell mixers (GCMs). This amplifies and mixes the signals from the antennas and converts the phase difference ΔΦ into an equivalent output voltage map suitable for an 18-bit analog-to-digital converter. Systematic optimization techniques were developed to maximize the third-order intercept point, and suppress flicker noise for the LNAs and GCMs, resulting in improved sensing accuracy. The overall system-level evaluation results showed state-of-art angle-of-arrival sensing capability with an upper limit error of 3.447°.