Design and improving the transition-band characteristic of a stepped impedance low pass filter for communication systems

High-speed mixed integrated circuits are playing a major role in wireless and mobile communication devices today. The increasing clock rates, higher packaging densities, compact geometries and the overall complexity have been some of the major concerns for the RF, microwave design engineer. The passive component, low pass filters are used for various wireless applications. In certain, low pass filters with high stop band attenuation and low insertion loss are used to suppress spurious signals & harmonics. These filters found frequent applications in mixers, equalizers, oscillators and other wireless communication systems. To design the proposed filter, a 8
^th
order lowpass filter prototype was simulated results are compared with the proposed data. In order to achieve this purpose we have designed and simulated C-band microstrip line low-pass filter (using microstrip lines) in ADS software. We have chosen the bandwidth of 4.5 GHz has been implemented with FR4 substrate and the relative permittivity 4.4 with thickness 62 mil. I have achieved the -3.003 dB at 4.5 GHz which is cut off frequency from the simulation result. The return loss is greater than -52 dB.