Substrate Integrated Waveguide Based Power Divider And Controllable Phase Shifters

Recent developments in the urge of discovering wide band and low cost microwave and millimetre wave devices, interconnects and circuits have immerged numerous novel ideas and techniques. Substrate Integrated Waveguide (SIW) technology has proven to be on top of all, owing to the exciting and application oriented advantages offered by SIW based devices and components. They are capable of providing all the useful characteristics of a classical milled metallic waveguide, while still keeping the cost as low as traditional microstrip based structures, as they can be realized using the well-known inexpensive printed circuit board (PCB) technique. On the other hand, they also inherit the advantages of microstrip structures for being low profile and advantages of metallic waveguide structures for being low in loss and providing high-Q factor.In this dissertation, some novel components based on SIW technology have been studied, designed, developed and explained. An introduction and several techniques to design SIW based components have been provided. Utilizing the advantages offered by SIW, a design of N-way SIW radial power divider has been studied and a complete generalized equivalent circuit model for such kind of power dividers has been discussed to enable the researchers to design this radial power divider according to their own needs. This power divider has proven to have low insertion loss (<0.45dB measured) and compact size. Secondly, a SIW based novel digital phase shifters with the capability of electronic control using PIN diodes has been proposed. This SIW based phase shifter introduces a new concept of controlling the phase by making the transverse slots etched over the top metal layer "enabled" or "disabled". This phase shifter is very simple in design and can provide90of electronically controllable phase shift for a low insertion loss, which is suitable for simplifying the design of phased array antenna systems. The structure of this phase shifter is low profile and the fabrication process is very simple. Furthermore, A multilayer SIW structure based electronically tunable phase shifter with its complete equivalent circuit model and design procedure has been investigated. The control over phase shift has been achieved by splitting the transverse slot used to couple the energy between the two layers in two slots and then varying the length of the slots electronically with the help of PIN diodes. This phase shifter has a wide bandwidth (33%) for a small insertion loss (<1.5dB) while providing180°electronically tunable phase shift with excellent amplitude and phase imbalance performance. Each chapter contains the comparison of the current work with the ones that are considered to be closest counterparts developed in recent few years.In the electronic control of such phase shifters, biasing network for PIN diodes can sometime be very tricky. A straightforward and easy to design biasing network for such devices using the thin isolating slots on the top surface of SIW has also been proposed in this thesis. This design eliminates the surplus complexity added by biasing networks in the design of electronically controllable phase shifters.