Different speech detection sensors have been developed over the years but they are limited by the loss of high frequency speech energy, and have restricted non-contact detection due to the lack of penetrability. This paper proposes a novel millimeter microwave radar sensor to detect speech signals. The utilization of a high operating frequency and a superheterodyne receiver contributes to the h...

Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn a...

A wireless and passive temperature sensor operating up to 800 °C is proposed. The sensor is based on microwave backscatter RFID (radio frequency identification) technology. A thin-film planar structure and simple working principle make the sensor easy to operate under high temperature. In this paper, the proposed high temperature sensor was designed, fabricated, and characterized. Here the 99% ...

Imaging of defects in engineering components is gaining importance and wider acceptability. Imaging enables automation of measurement process by the use of sensor, enhanced detection and characterisation of defects. Further, it helps in assessing incremental damage in a critical region by performing periodic imaging and comparing. Raster-scan based single sensor imaging and line-scan based arra...

BACKGROUND Microwave heating is one of the most attractive cooking methods for food preparation, commonly employed in households and especially in restaurants for its high speed and convenience. The chemical constituents of oils that degrade during microwave heating do so at rates that vary with heating temperature and time in a similar manner to other type of processing methods. The rate of qu...

A highly sensitive, passive relative humidity (RH) sensor using polyvinyl-alcohol (PVA) dielectric film is presented. For the first time, PVA is investigated in microwave RF sensing devices for low cost, high resolution and accurate chipless RH sensor realization. Comparative study with traditional humidity sensing Kapton polymer is presented to validate superior performance of PVA film. Result...

A high-resolution fiber Bragg grating (FBG) sensor system using a linear-cavity fiber laser scheme is proposed and numerically studied. The proposed sensor system can improve the sensing accuracy by using a discriminating FBG pair in conjunction with a fiber laser scheme. This FBG sensor system can resolve the temperature up to 0.0005°C theoretically and can be applied for strain sensing and te...

1. ABSTRACT The multi-layer dense media radiative transfer (DMRT) theory based on the quasicrystalline approximation (QCA) has been applied for studying both passive and active microwave remote sensing signatures [1], [2]. It is shown that the layered structure is essential to analyze the microwave emission from snow because high frequency is sensitive to the scattering from the medium top and ...

Nondestructive Testing (NDT) assessment of materials' health condition is useful for classifying healthy from unhealthy structures or detecting flaws in metallic or dielectric structures. Performing structural health testing for coated/uncoated metallic or dielectric materials with the same testing equipment requires a testing method that can work on metallics and dielectrics such as microwave ...

For four decades, satellite-based passive microwave sensors have provided valuable snow water equivalent (SWE) monitoring at a global scale. Before continuous long-term SWE records can be used for scientific or applied purposes, consistency of SWE measurements among different sensors is required. SWE retrievals from two passive sensors currently operating, the Special Sensor Microwave Imager So...