Magnetic Tuning of Three-Pole Microstrip Bandpass Filter

Abstract

Lot of work on frequency tuning in resonators and filters with magnetic biasing fields have been reported. Normally the frequency shifts are due to variation of ferrimagnetic resonance of substrate material. In the present paper we have reported the frequency tuning of three-pole microstrip bandpass filter by varying the relative permeability of the substrate material with the externally applied dc biasing magnetic field. For this a three-pole microstrip bandpass filter with a center frequency 2.8 GHz was fabricated using a thick silver film deposited on LiZnTi polycrystalline ferrite substrate. A tunability of 17 MHz in the moderate range of applied magnetic field was observed at room temperature. Fabricated device shows the negligible variation in its transmission loss in the presence of biasing field.

Additional information

Notes on contributors

Ashish Dubey

Ashish Dubey was born in Lucknow, in 1977. He received the MSc degree in Physics with specialization in Electronics from Christ Church College of Kanpur University in 1998 and the PhD degree in Microwaves from Dayalbagh Educational Institute, Agra, India in 2003. He is the recipient of various prestigious fellowships of DST and CSIR, Govt of India. His research activities were concerned with magnetically tunable microwave passive devices and components using polycrystalline ferrites. He published more than 10 papers in journals and conference proceedings of international repute. Currently he is working as scientific faculty at Physical Research Laboratory, Ahmedabad, India, and the present research interest is in sub-millimeter wave science and applications.

G S Tyagi

G S Tyagi born in 1954, obtained PhD degree in 1980 from Birla Institute of Technology & Sciences Pilani, Rajasthan, Joined Dayalbagh Educational Institute, Dayalbagh Aga, UP in 1983. Presently working as a Reader in Dept Physics and Computer Science at Dayalbagh Educational Institute, Agra. Published several research papers in national & international journals. Currently he is working on polycrystalline ferrite based microwave tunable devices.

V G Das

V G Das obtained his PhD in Elect Engg in 1978 from IIT Delhi. He is currently working as Professor & Head of Physics and Computer Science Dept at Dayalbagh Educational Institute, Agra. His areas of specializations are Signal Processing and Electronics.