The novel reconfigurable double-layer half-mode SIW filter with tunable DMS structure

ABSTRACT

The contribution of this paper is to present a reconfigurable double-layer half-mode substrate integrated waveguide (HMSIW) bandpass filter with continuous center frequency and 3 dB bandwidth (BW) tuning capabilities. The double-layer rectangular HMSIW is subjected to vertical electrical coupling and magnetic coupling through the proposed semicircle aperture and rectangular slot etched on the middle metal layer. Due to this mixed electric and magnetic coupling structure, the 3 dB BW can be tuned and one adjustable transmission zero (TZ1) is introduced. Varactors (CV2) are used to adjust the center frequency. The parasitic passband produced by the higher-order mode TE₁₀₂ can be suppressed, thanks to the proposed T-shapes defected microstrip structure. Compared with the conventional horizontal coupling SIW filters, the proposed HMSIW filter also shows a compact physical area. To demonstrate the proposed design method, a double-layer HMSIW bandpass filter is fabricated and measured. Both the simulation and measured results show a center frequency tuning range of 1.21–1.72 GHz, as well as demonstrate a 3 dB BW tuning range of 62–101 MHz around 1.21 GHz, 97–213 MHz around 1.45 GHz, 225–310 MHz around 1.72 GHz. The insertion loss ranges from 1.18 to 6.32 dB. Furthermore, simulated and measured results also show a good agreement.

KEYWORDS:

• Double-layer HMSIW
• tunable frequency
• tunable 3 dB bandwidth
• vertical coupling
• defected microstrip structure

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 61671195 and 61372020].

Notes on contributors

Bin You

Bin You received the M.S. degree from Lanzhou University, Lanzhou, China, in 2000, and the Ph.D. degree from Shanghai University, Shanghai, China, in 2003. Since 2005, she was a Lecturer with the faculty of School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, China, and was promoted to Professor in 2016. Her current research interests include RF, microwave and mm-wave filter, and RF system design.

Linyun Chen

Linyun Chen received the B.S. degree from Hangzhou Dianzi University, Hangzhou, China, in 2015, the M.S. degree from Hangzhou Dianzi University, Hangzhou, China, in 2018. His current research interests are in RF, microwave and mm-wave filter design.

Guoqing Luo

Guoqing Luo (M’08) received the B.S. degree from the China University of Geosciences, Wuhan, China, in 2000, the M.S. degree from Northwest Polytechnical University, Xi’an, China, in 2003, and the Ph.D. degree from Southeast University, Nanjing, China, in 2007. Since 2007, he was a Lecturer with the faculty of School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, China, and was promoted to Professor in 2011. From Oct. 2013 to Oct. 2014, he joined the Department of Electrical, Electronic and Computer Engineering, Heriot-Watt University, Edinburgh, U.K., as a Research Associate, where he was involved in developing low-profile antennas for UAV applications. He has authored or co-authored over 70 technical papers in refereed journals and conferences and holds 16 patents. His current research interests include RF, microwave and mm-wave passive devices, antennas, and frequency selective surfaces.