A 60 GHz liquid sensing substrate integrated cavity in LTCC

This paper presents a 60 GHz liquid sensing cavity resonator realized in LTCC technology for liquid sensing applications, such as in lab-on-chip microfluidics. The LTCC cavity senses the liquid through means of an opening in the cavity's bottom metal layer. Different liquids underneath the cavity result in different resonant frequencies and coupling levels of the cavity. Measurements were performed with water-methanol mixtures, resulting in an observed 400 MHz shift of maximum coupling frequencies and 0.8 dB of maximum coupling levels.