<p>Microstrip antenna-based sensors are increasingly being adopted in the oil industry due to their compact structure, affordability, and ability to analyze complex fluid compositions. This research introduces a sample channel-integrated antenna sensor operating at a resonance frequency of 2.42 GHz, capable of accurately assessing spectral responses for 40 oil samples of two different brands of mustard oil 20 each adulterated with palm and soya with a constant 20 mL sample volume. The final prototype was developed on a cost-efficient FR-4 substrate, incorporating a sample channel to facilitate the injection and analysis of adulterated oil samples. The sensor measures 40 × 40 × 1.6 mm³. Initially, pure samples of mustard, palm, and soybean oils were characterized using the sensor. Subsequently, mustard oil from two different brands was adulterated with refined palm and soybean oils and tested by directly applying the mixtures onto the sensors sample channel. Experimental results demonstrated the sensor’s ability to identify adulteration levels from 5 to 50% in the tested oil samples. Among the key performance indicators, the sensor achieved a peak sensitivity of 0.01. Overall, the paper presents a sample channel-integrated microstrip antenna sensor operating at 2.42 GHz for controlled and repeatable quantitative detection of edible oil adulteration, enabling multi-brand and multi-adulterant analysis using a compact and cost-effective platform for real-time monitoring in oil industry.</p>