Finite Element Modeling of Electromagnetic Scattering for Microwave Breast Cancer Detection

Microwave tomography is an imaging modality which uses the contrast between the tissues. The high contrast between breast normal tissue and the malignant tissue makes the microwave imaging a proper option for breast cancer detection. In a typical microwave imaging problem, the breast is illuminated by the microwave antennas surrounding it. Forward model solves the underlying Helmholtz equation to achieve the electromagnetic fields at the location of receiving antennas. The predicted fields may be used in an iterative inversion algorithm to reconstruct the tumor and the other unknown boundaries.
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Time Matters — How Power Meters Measure Fast Signals

Modern peak power meters can measure virtually all types of pulsed or repeating signals. To achieve this, these instruments are equipped with sophisticated trigger capabilities. Prerequisite to any fast measurement is the synchronization of the instrument’s measurement cycle to the actual event. Simply put, the input signal of interest has first to be “found.” Specific trigger settings prepare the instrument for this synchronization and, once the desired event occurs, provide stable signal representations, allowing detailed signal analysis and accurate measurements. To be able to “look ahead,” digital instruments often use special techniques such as circular acquisition buffers to facilitate display and measurement of pre-trigger events. Most RF peak power meters provide internal and external trigger capabilities. Internal triggering utilizes the envelope of the actual incoming RF signal, while external triggering utilizes a baseband trigger signal that is in some way synchronized with the RF input signal.
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