Siddiqui Omar, Ramzan Rashad, Amin Muhammad, Ramahi Omar M
College of Engineering, Taibah University, Madinah, Saudi Arabia.
Department of Electrical Engineering, UAE University, Al-Ain, United Arab Emirates.
Sci Rep. 2016 Jun 27;6:28626. doi: 10.1038/srep28626.
The traditional microwave resonance sensors are based on the measurement of the frequency shift and bandwidth of a resonator's amplitude spectrum. Here we propose a novel sensing scheme in which the material properties are estimated by determining the changes in the phase spectrum of an anomalous-phase resonator. In the proposed phase sensing, we exploit the unique double phase reversal which takes place on the edges of the anomalous dispersion region as a signature to detect the resonance. We show that with the phase sensing, a significant reduction in detection errors compared to the traditional sensing can be obtained because of the noise immunity offered by the phase detection and also due to the strong dispersive phase response that reduces the sensor's dependence on the external environment. We also show that the bandwidth determination procedure of the resonance which is needed to characterize the sample losses is significantly simplified. The concept of phase sensing is shown by devising an experimental microstrip open stub resonator whose frequency response lies in the anomalous dispersion region. The dielectric characteristics of the samples placed on the stub are extracted from the resonant frequency and the slope of the phase response. We also demonstrate that the changes in moisture levels can also be detected by utilizing the phase sensing method.
传统的微波共振传感器基于对谐振器幅度谱的频移和带宽的测量。在此，我们提出一种新颖的传感方案，其中通过确定反常相位谐振器的相位谱变化来估计材料特性。在所提出的相位传感中，我们利用在反常色散区域边缘发生的独特双相位反转作为检测共振的特征。我们表明，通过相位传感，与传统传感相比，由于相位检测提供的抗噪声能力以及降低传感器对外部环境依赖性的强色散相位响应，可以显著降低检测误差。我们还表明，表征样品损耗所需的共振带宽确定过程被大大简化。通过设计一个频率响应位于反常色散区域的实验性微带开路短截线谐振器来展示相位传感的概念。从谐振频率和相位响应的斜率中提取放置在短截线上的样品的介电特性。我们还证明，利用相位传感方法也可以检测湿度水平的变化。
