Microfluidically Loaded Highly Reconfigurable Compact Antennas & RF Devices

Authors: Gokhan Mumcu

Source: FERMAT, Volume 19, Communication 10, Jan-Feb., 2017

Abstract: Reconfigurable radio frequency (RF) antennas and filters have drawn growing interest to enable compact and light-weight multifunctional systems for wireless communications, sensor networks, biomedical imaging, and remote sensing. Existing reconfigurable RF device design approaches that are based on material loadings, semiconductor and ferroelectric varactors, micromechanical systems (MEMS) switches and capacitors are today well-recognized to offer compact and cost-effective device implementations with high reconfiguration speeds. However, these technologies continue to exhibit limited performance in terms of key RF metrics such as power handling, frequency tunability bandwidth, pattern scanning range, efficiency, and frequency-agile capability. Consequently, novel alternative techniques that address the overall performance needs of reconfigurable RF devices are highly desirable to advance their capabilities and use into mainstream technologies. This presentation focuses on novel reconfigurable RF antennas, filters, and imaging systems realized by resorting to innovative microfluidic based reconfiguration techniques. The operational principles of these devices rely on continuously movable microfluidic loads consisting of metal (in liquid or solid form) and dielectric solution volumes. The realization of the devices are carried out by utilizing microfluidics and microfabrication techniques with multilayered ultra-thin substrates to maximize the parasitic loading effect of the microfluidic loads for achieving high reconfiguration performances. It will be shown that the proposed microfluidic reconfiguration techniques offer significantly improved frequency tuning range (>4:1 and >2:1 in monopole antenna and filter topologies, respectively) without suffering from excessive loss factors and high power handling issues observed in conventional semiconductor based implementations. Another example design will demonstrate that the microfluidic reconfiguration techniques lead to low-cost mm-wave (30GHz) beam-scanning high-gain antenna arrays without necessitating the use of costly and lossy phase shifters.

Index Terms: Reconfigurable antenna, filter, mm-wave, antenna array, microfluidics, liquid metal

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Microfluidically Loaded Highly Reconfigurable Compact Antennas & RF Devices