Compact Lowpass Filter with Ultra-High Figure-of-Merit and Flat Group Delay

ABSTRACT

This paper presents a microstrip lowpass filter with compact size, and ultra-wide stopband. The structure consists of a modified hairpin resonator loaded with tapered cells and the circular patches as the suppressing cell. The proposed lowpass filter has −3 dB cut-off frequency at 1.64 GHz. It also has suitable performances such as: ultra-sharp transition-band of 0.09 GHz that is from −3 to −20 dB, an extended stopband bandwidth from 1.73 to 21 GHz with the attenuation level more than −20 dB, low insertion-loss, flat group delay in the passband, and simple structure. The proposed lowpass filter is simulated and fabricated and there is good agreement between the simulation and measurement results.

KEYWORDS:

• Microstrip lowpass filter
• Sharp roll-off
• Ultra-high figure-of-merit
• Ultra-wide stopband

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Mohsen Hayati

Mohsen Hayati received the BE degree in Electronics Engineering from Nagarjuna University, India, in 1985, and the ME and PhD degrees in Electronics Engineering from Delhi University, India, in 1987 and 1992, respectively. Currently, he is a professor with the Electrical Engineering Department, Kermanshah branch, Islamic Azad University and the Electrical Engineering Department of Razi University. He has published more than 195 papers in international, domestic journals, and conferences. His current research interests include microwave and millimetre wave devices and circuits, application of computational intelligence, artificial neural networks, electronic circuit synthesis, modelling and simulations.

E-mail: [email protected]

Milad Ekhteraei

Milad Ekhteraei was born in Kermanshah, Iran in 1989. He is currently working towards the PhD degree in electrical engineering in Azad University, Kermanshah, Iran. He received the BSc degree in electrical engineering from Islamic Azad University, Kermanshah branch, Iran, in 2012 and MSc degree in electrical engineering from Islamic Azad University, Arak branch, Iran, in 2014. His research interests include design and analysis of microstrip filters.

E-mail: [email protected]

Farzin Shama

Farzin Shama is currently working towards the PhD degree in electrical engineering in Razi University, Kermanshah, Iran. His research interests include analogue circuits and design, microwave engineering, and passive and active circuits design and fabrication. He was proud to achieve the superior researcher in the engineering faculty of Razi University, in 2011 and 2012. Also, he has been selected as the top student of Iran in PhD degree – awarded by the first Vice President of Iran in 2015.

E-mail: [email protected]

Hamid Sherafat Vaziri

Hamid Sherafat Vaziri was born in Kermanshah, Iran in 1985. He received the BE and ME degrees in electrical engineering from Razi University, Kermanshah, Iran. He is currently working towards the PhD degree in electrical engineering in Razi University, Kermanshah, Iran. His research interests include microstrip filter design and fabrication.

E-mail: [email protected]