The Design and Investigation of the Low-Pass Filter with High Selectivity and Ultra-Wide Stopband

Abstract

In this work, an ultra-wide stopband low-pass filter (LPF) is proposed using tapered step impedance resonators. The distributed equivalent of the proposed step impedance LPF is extracted, analyzed, and legitimated with simulated and fabricated results. The fabricated prototype has a 3 dB cut-off frequency (f_c) of 2.92 GHz and an ultra-wide stop band extended up to 25.7 GHz (8.8fc) with an attenuation level of >20 dB. The transition bandwidth (from 3 to 20 dB) is 0.20 GHz and the roll-off factor is 112 dB/GHz (a reference to 30 dB). The passband insertion loss is 0.32 dB at 1.5 GHz and the normalized circuit size of the filter is 0.055.

KEYWORDS:

• Quarter wave open stubs
• Roll-off factor
• Tapered step impedance resonator
• Wide stopband

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Pankaj S. Tomar

Pankaj Singh Tomar received the BE degree in electronics engineering and M Tech degree in microwave engineering from Rajiv Gandhi Proudyogiki Vishwavidyalaya Bhopal, India. He is currently pursuing PhD degree with the Department of Electronics and Communication Engineering, Indian Institute of Information Technology, Design and Manufacturing (IIITDM) Jabalpur, Jabalpur, India. His current research interests include reconfigurable filters and antennas, microwave integrated circuits, RF/microwave passive circuits and microwave, and millimeter-wave device characterization. Corresponding author. Email: [email protected]

Manoj S. Parihar

Manoj Singh Parihar received the BE and MTech degrees from Rajiv Gandhi Proudyogiki Vishwavidyalaya Bhopal, Bhopal, India, in 2001 and 2004, respectively, and a PhD degree from IIT Delhi, New Delhi, India, in 2012. From 2010 to 2013, he was senior project scientist with the Center for Applied Research in Electronics, IIT Delhi. In 2007, he received an Institute of Electronics and Telecommunication Engineers Research Fellowship for continuing his research work in reconfigurable antennas at IIT Delhi, and simultaneously, he was selected for the invitation program sponsored by the National Institute of International Education of the Ministry of Education and Human Resources of Republic of Korea to visit Korean Universities and Industries. He is currently assistant professor with the Indian Institute of Information Technology, Design and Manufacturing Jabalpur, Jabalpur, India. His current research interests include reconfigurable antennas,microwave integrated circuits, microwave and millimeter-wave device characterization, and RF MEMS. Email: [email protected]