Abstract:
This dissertation deals with the simulation, design, analysis of Non-Radiative Dielectric (NRD) guide based circuits and NRD transitions. NRD guide is a type of waveguide where a dielectric strip is kept between two metal plates separated by distance less than the half of the free space wavelength. Here Polylactic Acid (PLA) is used as the dielectric medium which is used as a cartridge in 3D printing. PLA is a type of bio-plastic which are basically plastics derived from biodegradable mass.One of the striking features of PLA is that it is biodegradable.The advantages and shortcomings of PLA have been discussed in detail. The electrical properties of PLA are mainly focussed where the low S21 values in the transition structures were attributed to high dielectric loss tangent value of PLA. In this thesis all the simulations were done using FEM simulator HFSS. The NRD transitions such as NRD to waveguide transitions, NRD to waveguide transition using horn antenna with E-plane flared and H-plane tapered, NRD to microstrip transition have been simulated. All the transition structures are analyzed with main focus around 47 GHz. The design and analysis of transition structures are of utmost importance so that NRD guide based circuits can be designed in the future. A bandpass filter and bandstop filter using NRD to waveguide transition were designed and simulated with a centre frequency of 47GHz. NRD to microstrip transition has been realized physically and the experimental results are discussed in detail. The shortcomings and their solutions have also been discussed. The field lines and propagation of different modes of the NRD structures have also been analyzed and solutions are provided if anomalies were found regarding it.
