摘要 |
<p>A sensor (10, 40) for measuring the ratio of fluids or other materials in mixture (12) utilizes a coplanar resonator. The resonator has an outer conductor or conductor plane (17, 41) that is on a semiconductor substrate (11). The conductor plane (17, 41) has an opening (18, 48) that exposes a portion of the surface of the substrate. An inner conductor or sensing element (19, 42) is formed on the exposed surface within the opening (18, 48) so that the conductor plane (17, 41) and the sensing element (19, 42) are coplanar. The sensing element (19, 42) is coupled to an input (22) of a transistor (21) to form an oscillator. The oscillator frequency varies as the ratio of materials in the mixture (12) varies. <IMAGE></p> |