High Performance Microstrip Low Pass Filter for Wireless Communications

A microstrip low-pass filter using T-shaped resonators is designed to achieve an ultra-sharp transition band and high suppression level. The performance of the resonators is investigated based on an LC equivalent circuit and a transfer function to compute the equations of the transmission zeros. This filter has an acceptable stopband with high insertion loss (28 dB) by adopting a rectangular suppressor. Also, the width of the transition band is 0.09 GHz (with – 3 and − 40 dB attenuation levels), that exhibits a very high sharpness (ξ = 411 dB/GHz). The proposed filter with a 3 dB cut-off frequency (fc) of 1.32 GHz presents a high return loss in the passband (17 dB) and high figure of merit of 57,073. The designed filter is fabricated and measured, demonstrating sufficient agreement between the simulation and experimental results.

[1]  D. Suhas,et al.  A systematic implementation of elliptic low-pass filters using defected ground structures , 2015 .

[2]  Jia-Sheng Hong,et al.  Microstrip filters for RF/microwave applications , 2001 .

[3]  Abbas Omar,et al.  High‐performance wide stop band low‐pass filter using a vertically coupled DGS‐DMS‐resonators and interdigital capacitor , 2014 .

[4]  Zhitao Xu,et al.  Compact lowpass filter with wide stopband using stepped impedance hairpin units , 2015 .

[5]  Ahmed Boutejdar,et al.  Design of a very compact U-HI-LO low-pass filter using meander technique and quasi horn inductors for L-band and C-band applications , 2016 .

[6]  Minquan Li,et al.  A novel sharp roll‐off microstrip lowpass filter with improved stopband and compact size using dual‐plane structure , 2016 .

[7]  A. K. Verma,et al.  High performance microstrip transverse resonance lowpass filter , 2013 .

[8]  P. M. Jasmine,et al.  Planar elliptic function lowpass filter with sharp roll‐off and wide stopband , 2016 .

[9]  M. Hayati,et al.  Compact lowpass filter with flat group delay using lattice-shaped resonator , 2017 .

[10]  Zhitao Xu,et al.  Sharp roll-off lowpass filter using interdigital DGS slot , 2015 .

[11]  Prashant Kumar Singh,et al.  Ultra‐compact switchable microstrip band‐pass filter–low‐pass filter with improved characteristics , 2017 .

[12]  Jia Bao,et al.  Stopband‐Extended and Size‐Miniaturized Low‐Pass Filter with Three Transmission Zeros , 2014 .

[13]  Wen Wu,et al.  Miniaturised microstrip lowpass filter with broad stopband and sharp roll-off , 2010 .

[14]  Mi Xiao,et al.  A Lowpass Filter With Compact Size and Sharp Roll-Off , 2015, IEEE Microwave and Wireless Components Letters.

[16]  Zbynek Raida,et al.  Lowpass filter with reduced fractal defected ground structure , 2013 .

[17]  Hui Lu,et al.  Compact lowpass filter with wide stopband bandwidth , 2015 .

[18]  Yong Fan,et al.  Compact ultra-wide stopband low pass filter using multimode resonators , 2015 .

[19]  Saeed Roshani,et al.  A compact microstrip low-pass filter with ultra wide stopband using compact microstrip resonant cells , 2016, International Journal of Microwave and Wireless Technologies.

[20]  S. Sanyal,et al.  Sharp Roll-Off Lowpass Filter With Wide Stopband Using Stub-Loaded Coupled-Line Hairpin Unit , 2011, IEEE Microwave and Wireless Components Letters.