Design of a microstrip band pass filter using half wavelength parallel-edge coupled line for improvement of passband characteristics

The Ultra-wideband systems are used in wireless communication system. It is capable of transmitting data over a spectrum of frequency band for short and long distances with a very low power and high data rates. A method used improving the bandwidth using half wavelength parallel-edge coupled micro strip line. A proto-type filter with centre frequency at 4.5 GHz and fractional bandwidth of 0.133 has been implemented with FR4 substrate and dielectric constant 4.2 with thickness 1.2 mm. The physical parameters of the parallel edge- coupled line band pass filter sections has been simulated using the ADS software. I have found the centre frequency at 4.271 GHz from the simulation result and bandwidth is also improved from 30% to 58%. The simulation return loss greater than -27.5 dB and measured insertion loss was found less than 0.14 dB at center frequency.