Comparative Study of Three DGS Unit Shapes and Compact Microstrip Low-Pass and Band-Pass Filters Designs

In this paper, three types of defected ground structure (DGS) units which are triangular-head (TH), rectangular-head (RH) and U-shape (US) are investigated. They are further used to low-pass and band-pass filters designs (LPF and BPF) and the obtained performances are examined. The LPF employing RH-DGS geometry presents the advantages of compact size, low-insertion loss and wide stopband compared to the other filters. It provides cutoff frequency of 2.5 GHz, largest rejection band width of 20 dB from 2.98 to 8.76 GHz, smallest transition region and smallest sharpness of the cutoff frequency. The BPF based on RH-DGS has the highest bandwidth (BW) of about 0.74 GHz and the lowest center frequency of 3.24 GHz, whereas the other BPFs have BWs less than 0.7 GHz.

Authors:

• M. Challal
• F. Labu
• M. Dehmas
• A. Azrar

Keywords:

• Defected ground structure (DGS)
• triangular-head(TH) DGS
• rectangular-head (RH) DGS
• U-shape (US) DGS
• lowpassfilter (LPF) and band-pass filter (BPF).

References:

[1] D. Ahn, J. S. Park, C. S. Kim, Y. Qian and Y. Itoh, "A Design of the
Low-pass Filter using the Novel Microstrip Defected Ground Structure,"
IEEE Trans. Microw. Theory Tech., vol. 49, pp. 86-91, 2001.
[2] X. Chen, L. Wang, L. Weng and X. Shi, "Compact low pass filter using
novel elliptic shape DGS," Microw. and Optical Technology Lett., vol.
51, no. 4, pp. 1088-1091, Apr. 2009.
[3] G. H. Li, X. H. Jiang and X. M. Zhong, "A novel defected ground
structure and its application to a lowpass filter," Microw. and Optical
Technology Lett., vol. 48, no. 9, pp. 1760-1763, Sep. 2006.
[4] S. K. Parui and S. Das "An asymmetric defected ground structure for
implementation of elliptic filters," AEU Int. J. of Electron. Commun.,
vol. 63, pp. 483-390, 2009.
[5] A. Rahman, K. Verma, A. Boutejdar and A. Omar, "Control of band
stop response of Hi-Lo Microstrip low pass filter using in ground plane,"
IEEE Trans. Microw. Theory Tech., v. 52, no. 3, pp. 1008-1013, Mar.
2004.
[6] A. Boutejdar, M. Challal and A. Azrar, "A Novel Band-Stop Filter
Using Octagonal- Shaped Patterned Ground Structures along with
Interdigital and Compensated Capacitors," ACES J. - The Applied
Comp. Electromagnetics Society, vol. 26, no. 4, pp. 312-318, Apr.
2011.
[7] M. Challal, A. Azrar and M. Dehmas, "Rectangular Patch Antenna
Performances Improvement Employing Slotted Rectangular shaped for
WLAN Applications," IJCSI- Int. J. of Comp. Science Issues, vol. 8,
issue 3, pp. 254-258, May 2011.
[8] M. Salehi and A. Tavakoli, "A novel low mutual coupling microstrip
antenna array design using defected ground structure," Int. J. Electron.
Commun., vol. 60, pp. 718-23, 2006.
[9] Y. T. Lee, J. S. Lim, J. S. Park and N. D. Sangwook, "A novel phase
noise reduction technique in oscillators using defected ground
structure," IEEE Microw. Guided Wave Lett, vol. 12, pp. 39-41, 2008.