Microfluidically Frequency-Reconfigurable Quasi-Yagi Dipole Antenna.

Syed Shah,Sungjoon Lim

doi:10.3390/s18092935

Abstract

In this paper, a frequency reconfigurable quasi-Yagi dipole antenna is proposed by leveraging the properties of microfluidic technology. The proposed antenna comprises a metal-printed driven dipole element and three directors. To tune resonant frequencies, microfluidic channels are integrated into the driven element. To maintain a high gain for all the tuned frequencies, microfluidic channels are also integrated into the directors. Therefore, the length of the driven-element as well as directors can be controlled by injecting liquid metal in the microfluidic channels. The proposed antenna has the capability of tuning the frequency by varying the length of the metal-filled channels, while maintaining a high gain for all the tuned frequencies. The proposed antenna’s performance is experimentally demonstrated after fabrication. The injected amount of liquid metal into the microfluidic channels is controlled using programmable pneumatic micropumps. The prototype exhibits continuous tuning of the resonant frequencies from 1.8 GHz to 2.4 GHz; the measured peak gain of the proposed antenna is varied in the range of 8 dBi to 8.5 dBi. Therefore, continuous tuning with high gain is successfully demonstrated using liquid-metal-filled microfluidic channels.

Highlights

The Yagi-antenna has received particular attention due to its interesting features, like simple structure, low profile, ease of fabrication and installation [1], high radiation efficiency [2], and unidirectional radiation with high gain [3,4,5,6]
A few frequency reconfigurable antennas have been reported by using ideal switches and varactor diodes
Microfluidically frequency-reconfigurable quasi-Yagi is by frequency-reconfigurable quasi-Yagi dipoledipole antennaantenna is presented by employing

Summary

Introduction

The Yagi-antenna has received particular attention due to its interesting features, like simple structure, low profile, ease of fabrication and installation [1], high radiation efficiency [2], and unidirectional radiation with high gain [3,4,5,6]. The operational frequency of the antenna was switched between 2.4 GHz and 5.78 GHz. A frequency-reconfigurable quasi-Yagi antenna was presented by employing varactor diodes in the driven elements as well as in the directors [14]. The resonant frequency of the antenna was tuned from 1.8 GHz to 2.4 GHz. The measured reported gain of the antenna was 5.6 dBi to 7.6 dBi. In [15], a frequency tunable Yagi antenna was presented aimed for wireless body area network applications. PIN diodes were installed in the driven elements and in the directors to tune the frequency and to achieve a high gain for each frequency. Frequency tuning by PIN diodes and varactor diodes are very effective in providing high-speed tunability They exhibit some drawbacks in terms of low frequency tunability range, reduced radiation efficiency, and lower power handling capability [22]. The antenna presents end-fire radiation pattern for all of the frequency bands

Antenna Design

Simulated

The gain

Experimental

Conclusions