Compact low‐cost microstrip lowpass filter with sharp roll‐off and wide attenuation band

Abstract

A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepped impedance resonator loaded with interdigital fingers and U-shaped resonator is recommended in this article. The proposed LPF has a cut-off frequency of 1.2 GHz with a sharp roll-off 135 dB/GHz and passband insertion loss 0.35 dB. An array of two different shapes of defected ground structures are etched in the ground plane for introducing additional transmission zeroes to enhance the stopband performance. The relative stopband suppression is achieved up to 171% with a suppression factor of 2. The proposed structure is modelled, fabricated, and measured. The measurement results are found to be well-matched with the simulated ones. Eventually, a high figure of merit of 21 600 is achieved. K E Y W O R D S defected ground structures, figure of merit, interdigital lines, lowpass filter, stepped impedance resonator, U-shaped resonator

Design and fabrication of MEMS lowpass filter exploiting space mapping algorithm

“…Planar microstrip LPF has attracted great attention due to its advantages of small size, low‐cost and easy of fabrication. To date, several structures have been reported to obtain high‐performance lowpass filters 1‐14 . In Reference 3, a microstrip low‐pass filter using a stepped impedance hairpin resonator with a pair of coupled stepped impedance resonators (SIRs) inside is presented.…”

“…In Reference 11, a microstrip LPF with sharp roll‐off and wide stopband consisting of radial split ring resonator loaded by folded polygene patches is proposed. In References 12 and 13, defected ground structures are adapted for performance improvement. In Reference 14, a microstrip LPF uses complementary rectangle split ring defected microstrip structure to improve the stopband and suppress the harmonic response.…”

Modified Wilkinson power divider with harmonics suppression and compact size for GSM applications

“…Radio frequency (RF)/microwave power dividers with good properties such as wide stopband, compact size, high suppression factor (SF), high isolation between output ports, and simple structure are widely used in modern wireless communication systems for dividing the input signal into two or more signals. Nowadays, filters 1–10 and power dividers 11–25 are widely used in microwave systems such as power amplifiers, mixers, and feeding network in an antenna array, because they are easily designed and fabricated with other microwave devices. In Reference 1, a compact low‐pass filter (LPF) with wide stopband using stepped impedance and open stubs is presented.…”

“…In Reference 1, a compact low‐pass filter (LPF) with wide stopband using stepped impedance and open stubs is presented. In References 2 and 3, an LPF with a sharp roll‐off rate (ROF) and wide stopband is presented. An LPF with multi open‐circuited shunt stubs is reported in Reference 4.…”