Designs Of A 2D Parallel Plate Waveguide Field Scanning System And Its Wave Launchers

2D parallel plate waveguide field scanning systems are constructed by upper and lower parallel conducting plates.The fundamental mode of the systems is the transverse magnetic fields relative to the plate normal,which is also the plane or cylindrical modes in free space.Hence,this system can mimic some electromagnetic wave propagations in free space,such as the wave scatterings of 2D objects,and is an effective electromagnetic wave measurement device.The thesis presents the designs of the hardware and software of a 2D parallel plate waveguide field scanning systems.The main work includes:1.Computer program coding to control the mechanical movement of the system and the vector network analyzer for measurement.The codes control the motion of the lower plate that is mounted on a 2D translation stage,and also control the vector network analyzer to scan the field distribution inside the 2D plate waveguide with an electric field probe installed on the upper plate.By analyzing the wave propagation properties,the device or material under test can be characterized.2.Applying the focusing lens principle to design a dielectric lens to produce plane wave inside the system.The FR4 dielectric substrate is shaped like a lens to convert a cylindrical wave to a plane wave through the difference in optical paths,which is used as the incident wave of the system for measurement.3.The boundary condition method is proposed to produce the arbitrary incident waves.The method is realized by using a power divider and a phase shifter to feed a patch antenna array.The power division ratio and phase shift at different output ports are designed so that the aperture field of the patch antenna array is approximately equal to the boundary distribution of the wanted field distribution.Thus,the wanted field can be produced because the boundary condition has been realized physically.We have designed plane wave and Gaussian wave launchers at different frequencies and with different wave beam parameters,and have performed experiments to verify our idea.The experimental results agree with the simulation and theoretical ones.These wave launchers can be used in the system to generate different incident waves for device and material measurements.The advantage of this method is being capable of producing arbitrary incident waves.