Imaging system for low density plasma with fan beam microwave and microstrip antenna

Summary form only given, as follows. When we measure the spatial distribution of the dielectrics, including 2D and/or 3D distribution, there are several methods to be known with the help of electromagnetic waves. We have performed experiments for measuring the spatial distribution of the plasma electron density with the microwave heterodyne interference method, which is assisted by the fan-beam microwave and the diode scattering techniques. The minimum spatial resolution is limited by the spacing of the diodes in the diode array and is almost the same size as or even less than the wavelength of the electromagnetic waves used in the system. In order to obtain better spatial resolution, we have used a microstrip antenna array instead of the diode array in our study. The fan shaped microwave beam with frequency of 24 GHz is launched from the horn antenna, which is used as a receiver of the scattered signals. The imaging phantoms we employed are the styrene foam. The signals are modulated with the EF frequency 35 MHz by each microstrip antenna array located behind the object. Those data are reconstructed with the computer through CT reconstruction method. A good imaging of the objects could be attained with the imaging system using the microstrip antenna. This imaging system could improve the spatial resolution and be applied to two dimensional system. We report the experimental results (reconstructed image) measured by the system with a microstrip antenna array.