Development of equal and unequal filtered power splitter using substrate integrated waveguide

Abstract

The objective of this thesis is to investigate and provide better solution to producing filtered power splitter with compact size and with use of no resistors for its isolation. The background investigation and utilisation of the established theories build up the design equations that are adapted to power dividers. These dividers contain filtering characteristics and are employed in microstrip and substrate integrated waveguide technology. The work involves the design of a filtered power splitter with bandpass characteristics. It uses the conventional filter design synthesis to develop the design parameters that establish the coupling between the common resonator of the power splitter and the next resonator towards the output ports. An equal and an unequal division using a 5-pole, 9-square resonators is used verify this concept; this is also implemented in microstrip using Square open loop resonators (SOLR) and in SIW. Furthermore, a 3-pole 5-square resonators is also implemented in SIW; all of these operating at 2 GHz. For the equal split, the 5th order microstrip gives a bandwidth, minimum insertion loss, maximum return loss and isolation of 120MHz, 3.12dB, 15dB and 12.6dB respectively and the 3rd order SIW gives a bandwidth, minimum insertion loss, maximum return and isolation of 99Mhz, 3.57dB, 17.1dB and 6.79dB respectively; whilst the 5th order SIW gives a bandwidth, minimum insertion loss, maximum return and isolation of 140Mhz, 3.87dB, 18.3dB and 14.79dB respectively. However, it is recommended that this work can be extended to more than two output ports, to improve isolation, increase the Q factor and match the output ports.