Enhancement of microwave ring resonator based on poly-lactic acid thermoplastic substrate

Fauziahanim Che Seman,Elfarizanis Baharudin,Nurul Hanani Manab,Rosnah Mohd Zin

doi:10.11591/eei.v9i6.1932

Fauziahanim Che Seman, Elfarizanis Baharudin + Show 2 more

Open Access

https://doi.org/10.11591/eei.v9i6.1932

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Abstract

In this paper, the development of a single-port microwave ring resonator (MRR) sensor based on a thermoplastic material, which is poly-lactic acid (PLA), is presented. The open-ended coaxial probe method was applied to identify the dielectric properties of PLA in terms of dielectric constant (2.25) and loss tangent (0.0001). The PLA substrate was fabricated using a hot press machine and with the same thickness (1.6 mm) as FR4. Hence, to consider the PLA as microwave substrate, microwave ring resonator (MRR) operating at 1.1 GHz resonance frequency was designed, simulated, and measured. Based on the observation, the return loss of MRR for the simulation and the measurement of the conventional design are -5.37 dB and -5.02 dB, respectively. The quality factor (Q-factor) for both are 122.22 and 183.33, respectively. Then, the enhanced coupling gap method was applied to improve the performance of MRR sensitivity in terms of return loss and Q-factor. It is observed that the return loss of the enhanced design for the simulation and the measurement are -26.67 dB and -20.23 dB, respectively, and the Q-factor are 122.22 and 200, respectively. Thus, the performance of the MRR based on different designs were compared in order to validate the sensor’s sensitivity and PLA can be recognized as a substrate material for RF and microwave applications.

Highlights

Microwave resonators are integral components in a microwave communication system and are used in a variety of applications including filters, oscillators, amplifiers and other applications that contain series and parallel RLC resonant circuits [1,2,3]
The RLC circuit is integral to the microwave ring resonator (MRR) structure’s design, which consists of the substrate, transmission line and patch [6,7,8]
The enhanced MRR design is proposed to overcome the low performance of the conventional MRR design

Summary

Introduction

Microwave resonators are integral components in a microwave communication system and are used in a variety of applications including filters, oscillators, amplifiers and other applications that contain series and parallel RLC resonant circuits [1,2,3]. The two criteria that describe the resonator are (i) the resonant frequency, wherein the energy in the cavity attains maximum value and (ii) Q-factor, which is the capacity of the electromagnetic energy storage. The Q-factor at low frequency is between 50 to 500, and the resonator bandwidth is inversely proportional to the Q-factor. A high Q-factor is obtained with the highly reactive RLC circuits [4, 5]. The RLC circuit is integral to the microwave ring resonator (MRR) structure’s design, which consists of the substrate, transmission line and patch [6,7,8]

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Results

Conclusion