A bi-patch loaded microstrip line based 1-D periodic structure with enhanced stop bandwidth and band switching characteristics

ABSTRACT

A one-dimensional periodic structure comprising of eight unit cells each having two metallic patches sandwiched between microstrip line and ground plane has been investigated. Patches bearing dissimilar dimensions present distinct reactive loads, determined by their respective areas, to generate relatively wider bandgap. Patches can be selectively connected to ground or left floating through a combination of vias and externally controlled FET switches. Dispersion analysis of the structure has been carried out to determine the propagating modes of the line for all four possible states of the unit cell. A top-down, design guide approach has been adopted with the effect of parameters determining performance attributes captured. The proposed structure acts as an all pass filter from DC to 19.5 GHz with all patches floating and exhibits stopband characteristics from 6 to 19.5 GHz with different combinations of the switches offering an overall stop bandwidth greater than 100%. The proposed structure offers tunability from no bandgap to bandgap with added advantages of band switching capability with double the number of unique reconfigurable switch patterns as compared to conventional single patch structures.

KEYWORDS:

• Electromagnetic band gap (EBG)
• periodic structures
• reconfigurable filters
• bandstop filters
• dispersion analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Irfan Shahid  http://orcid.org/0000-0003-4137-2161

Additional information

Funding

This work is supported by International Macquarie University Research Training Program.

Notes on contributors

Irfan Shahid

Irfan Shahid received his BE and MS degrees from NUST, Pakistan and UESTC, China, respectively. He is currently a PhD candidate at Macquarie University. His research interests include circuits for microwave applications.

Dushmantha Thalakotuna

Dushmantha Thalakotuna received his BS and PhD degrees from University of Marotuwa and Macquarie University, respectively. He is currently a lecturer at Macquarie University. His research interests include MMIC, RFIC and antennas.

Michael Heimlich

Michael Heimlich received his BS, ME and PhD degrees from Rensselaer Polytechnic Institute. He is currently a professor at Macquarie University. His research interests include RF/microwave MMIC and RFIC modelling, design flow theory, adaptive and reconfigurable wireless circuits, UWB for medical body area networks (MBAN), millimetre-wave packaging and GHz signal integrity.