1,721,065 research outputs found
Incoherent Migration for Near-Field Imaging by Uncharaterized Antennas
No full textIn this paper we present an incoherent migration (IM) algorithm for near-field reconstructions and without knowing the antenna's response. An analytical study is presented to compare the achievable performance by IM against its coherent counterpart. Numerical examples employing two different type of antennas whose responses are not accounted for in the reconstruction process show that IM does not suffer from antenna uncertainties
Slot Antennas for Microwave Brain Imaging by Accounting the Role of Hair
No full textIn this contribution, we describe and validate slot antennas for microwave brain imaging. The antenna consists of a slot enclosed within a cylindrical brick containing coupling liquid medium. Numerical examples and experiments on a few real human heads show that the proposed antenna exhibits S11 below -10 dB over the selected frequency band [1], [2] GHz
Inverse Scattering in a Multipath Environment
Get PDFIn this contribution an inverse scattering problem is ad- dressed in a multipath environment. In particular, multipath is created by known ”extra” point-like scatterers (passive elements) expressely deployed between the scene under in- vestigation and the source/measurement domains. Through a back-projection imaging scheme, the role of the passive elements on the achievable performance is shown and com- pared to the free-space case
Method for Robust Estimation of the Resonance Frequency of Microwave Biosensors
No full textIn this work, a procedure for robust estimation of the resonance frequency of microwave biosensors is presented. Usually, the sensor response is captured at a finite number of frequencies. Hence, inadequately fine frequency sampling step and the presence of noise negatively affect the estimation quality. The possibility to robustly evaluate the resonance frequency by exploiting efficient spectral estimation algorithms is demonstrated in the present contribution. This allows the use of inexpensive and lightweight devices suitable for self-monitoring. The method is validated against numerical and experimental data, the latter referring return loss measurements of a microwave patch antenna used for blood glucose monitoring
Resonant Modified Patch Sensor For Noninvasive Blood Glucose Monitoring
No full textIn this article, a low-cost microwave modified patch resonator (2.3 GHz) is presented for glucose level monitoring purposes. In practical cases, the correct monitoring could be compromised by a number of factors: system noise, environmental temperature and all those factors that affect the dielectric properties of tissues, (e.g., variation across the population in tissue thickness). In order to mitigate a such drawback a solid 'matching layer' is interposed between the patch antenna and the phantom under test. Numerical results confirm that this solution allows to achieve a good trade-off between measurement stability and sensitivity, allowing to discriminate glucose concentrations in the range of [100-600] mg/dL
Design Strategy of Microwave Resonant Sensors with Stable Response for Blood Glucose Monitoring
No full textMicrowave signals have gained significant interest for emerging medical applications. An example includes blood glucose monitoring where the complex scenario can compromise an accurate sensing, due to a number of factors, such as system noise, environmental temperature, and all those factors affecting the dielectric properties of tissues (e.g., variation across people). In order to mitigate such a drawback, a modified patch resonator (2.3 GHz) with a solid "matching layer"interposed between a traditional microstrip antenna and the phantom under test, is presented. Numerical results confirm this solution allows to achieve a good trade-off between measurement stability and sensitivity, allowing to discriminate glucose concentrations in a broad range from 100 up to 350 mg/dL
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