Heuristic Topology for Designing Reconfigurable Balun Active Filter for Frequency, Bandwidth and Power Division Ratio

Abstract

A novel concept of balun bandpass reconfigurable active filter is proposed here. The structure is composed of a three-stage balun filter having fractional bandwidth (FBW) of 13% with matched amplifier inserted between the last two stages. This technique of incorporating active device in balun filter gives an advantage of obtaining re-configurability, while compensating for loss at the balanced ports. The modified structure is able to yield re-configurability of frequency, bandwidth, power division ratio (PDR) and wide band stop response along with reduction in size (77 mm × 42 mm). The amplifier is accommodated within the second loop and is not cascaded with the balun filter, thus saving the space. The proposed balun filter has a varying gain of approximately 4–11 dB as bias changes from I_ds=52 to I_ds=78 mA, while simulating in MWO AWR software. The active balun filter has been fabricated on RT Duroid substrate. The measured results show | S₁₁| < −15 dB from 1.9 to 2.18 GHz, which is comparable with simulation results. The novelty of this work is to obtain bias-dependent frequency, bandwidth and PDR re-configurability with varying gain.

KEYWORDS:

• Active device
• Balun filter
• Bandpass
• Gain
• Reconfigurable

Additional information

Notes on contributors

Shikha Swaroop Sharma

Shikha Swaroop Sharma was born in New Delhi, India, in 1989. She received MTech degree in engineering physics from Guru Gobind Singh Indraprastha University, New Delhi, India in 2013, and is currently pursuing the PhD degree at the Birla Institute of Technology, Ranchi, India. Her research is focused on the development of new techniques for the design of reconfigurable active filter.

Anjini Kumar Tiwary

Anjini Kumar Tiwary was born in Jamshedpur, India in 1972. He received ME and PhD degrees in wireless communications from Birla Institute of Technology, Ranchi, India. Currently, he is assistant professor in the Department of Electronics and Communication Engineering, Birla Institute of Technology, Ranchi, India. He has authored and co-authored 6 journals and 13 conference papers. His research interests are RF circuits and antennas. Email: [email protected]