Slots and Defected Ground Structures Based Microstrip Lowpass Filter with Wide Passband

This paper proposes a microstrip lowpass filter operating at a higher cut-off frequency of 10.3 GHz with very wide passband characteristics, compact size, and low insertion loss. The designed filter is modeled using U-shaped slots in the signal plane and an array of I-shaped defected ground structures etched in the ground metallic plane. The integrated effect of the slots and defected ground structures provides the desired response. The designed structure has a circuit size of 90 mm2, a minimum insertion loss of 0.2 dB, and attenuation band up to 14.5 GHz. A broaden passband is obtained from 0.2 to 9.13 GHz with low insertion loss. The stopband is attenuated with −20 dB rejection level and relative stop bandwidth of 34%. The structure is designed on very low-cost FR4 substrate and is simulated in IE3D electromagnetic simulation software. The circuit simulated results are also obtained and is compared with the electromagnetic simulated results.