A Fan Beam Microwave CT System Which Determines the Straight Transmission Path by Time-Domain Measurement of Demodulated dc Voltage

摘要

We have developed a demodulated direct current voltage-based microwave CT system (dc-MCT) based on chirp-pulse microwave CT. The dc-MCT utilizes time-domain measurement to determine the shortest propagation path between the transmitting and receiving antennas. By using a standard SG with low phase noise and phase synchronization of the signal source, reconstructed amplitude and phase images can be obtained. In a study of high-speed imaging, the method of measurement and the influence of overshoot characteristics from the low-pass filter were examined, and the images were evaluated using 50 and 72 rotary scans. In addition, for the purpose of improving resolution, an attempt to obtain a time-domain spectrum that gives the maximum value of the amplitude showed the possibility of improving the dynamic range of the receiver. Thus this paper demonstrates the usefulness of the new method of microwave imaging.