A novel liquid adulteration sensor based on a self complementary antenna

In this paper, a novel OLR loaded self complementary dipole antenna (OSCDA) is proposed. Open loop resonators (OLRs) are introduced into the design of a traditional self complementary dipole antenna (SCDA), to evolve it into OSCDA. The antenna is compact and has an impedance bandwidth of 1.1 GHz to 3.3 GHz with VSWR less than 2 across the frequency band. The use of the proposed antenna as a liquid sensor to detect adulteration in liquids is demonstrated from the relationship between concentration and shift in resonant frequency and variation in reflection coefficient. Variation of reflection coefficient due to change in dielectric properties is studied for different cases viz.: (i) dilution of milk with water, (ii) adulteration of coconut oil with rice bran oil, (iii) adulteration of honey with sugar syrup, and (iv) varying concentration of salt and sugar in water. When an adulterant is added to a liquid or concentration of solute in a solution varied, the dielectric properties change. This is reflected in the variation in reflection coefficient and resonant frequency. Experimental results show that the antenna has a good sensitivity to detect adulterated samples.