A novel inkjet-printed microfluidic tunable coplanar patch antenna

In this paper, a novel inkjet-printed microfluidic tunable coplanar patch antenna combining microfluidic-based sensing technology and inkjet printing technique is proposed. The antenna is fabricated using a rapid, low-cost, and environmental friendly inkjet printing process on paper substrate. Based on the fluid pumped in the sensor, the resonant frequency of the antenna is tuned due to variation in the fluid permittivity. 13% frequency shift can be easily achieved, which verifies that the sensitivity of this antenna is good and allows for an easy tunability of the operating frequency from 3.8 GHz, for an empty microfluidic channel, to 3.3 GHz, for a water-filled channel. The antenna features a return loss better than 30 dB in the tunable frequency range of 3.5 to 3.8 GHz. This antenna can be used in multiple applications such as liquid monitoring and identification, bio-liquids sensing as well as low-cost reconfigurable antennas with the advantage of requiring the use of less than 25 uL of liquid.