Design of single and multilayer interdigital band pass filter

Abstract

Nowadays, there are many new telecommunication technologies developed such as wireless LAN and Bluetooth technology. Filters are essential to the operation of this technology. Interdigital filter is one of the available compact configurations. This thesis focuses on the design of two sets of interdigital band pass filter on single and multilayer structures at 2.45 GHz. Two designs have been proposed; asymmetrical and symmetrical interdigital band pass filters. They were designed using Mathcad mathematical software and electromagnetic simulations were done using Sonnet V9.52 simulator. The results showed that each filter operates well at the frequency of operation. Asymmetrical filters have excellent return losses of over -20 dB at the center frequency and minimized ripple from 0 to 2.79 dB. In contrast, symmetrical interdigital band pass filters have narrower bandwidth from 5.71% to 14.69% and very sharp roll off factor that can go up to 192.53 dB/GHz. Finally, the multilayer configuration showed that with the addition of dielectric substrates, the center frequency is shifted to 2 GHz and the bandwidth is broaden up to 50.6%