Compact and high performance microstrip diplexer for GPS and WLAN application

In this article, a novel compact and high performance microstrip diplexer is designed for global position system (GPS) and wireless local area network (WLAN) applications. The compact diplexer consists of two filters with short centered stepped impedance resonators (SCSIRs) and quarter-wavelength resonators (QWRs), operated at 1.575 GHz and 5.8 GHz, respectively. Due to the intrinsic characteristics and mutual loading effect of two filters, multiple transmission zeros can be generated to achieve sharp skirt, wide stopband, and high isolation of the diplexer. Moreover, more compact size can be obtained without the extra junction matching. Finally, a microstrip diplexer with 1 dB absolute bandwidth 100 MHz for GPS channel and 1 dB fractional bandwidth (FBW) of 3.45% at 5.8 GHz for WLAN channel is designed and fabricated. The simulated and measured results show a better agreement and validate the proposed theory. The size without the 50 Ω feedline is only 0.156 λg × 0.103λg, in which λg is the guided wavelength at 1.575 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1233–1237, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27550

[1]  G. L. Matthaei,et al.  Multiplexer Channel-Separating Units Using Interdigital and Parallel-Coupled Filters , 1965 .

[2]  Ming-Tien Wu,et al.  Microstrip Diplexer Design Using Common T-Shaped Resonator , 2011, IEEE Microwave and Wireless Components Letters.

[3]  Yong-Xin Guo,et al.  Design of compact bandpass filter with improved selectivity using source-load coupling , 2010 .

[4]  L. Athukorala,et al.  Compact Dual-Mode Open Loop Microstrip Resonators and Filters , 2009, IEEE Microwave and Wireless Components Letters.

[5]  Jie Zhan,et al.  Compact CPW-fed antenna with two asymmetric U-shaped strips for UWB communications , 2012 .

[6]  Tatsuo Itoh,et al.  Substrate Integrated Waveguide Loaded by Complementary Split-Ring Resonators for Miniaturized Diplexer Design , 2011, IEEE Microwave and Wireless Components Letters.

[7]  Chung-I G. Hsu,et al.  Bandpass filter of forked step impedance resonator with harmonic suppression in diplexer applications , 2007 .

[8]  R. J. Wenzel.  Printed-Circuit Complementary Filters for Narrow Bandwidth Multiplexers , 1968 .

[9]  Kai Chang,et al.  Stub-tuned microstrip bandpass filters for millimeter-wave diplexer design , 2005 .

[10]  Tao Yang,et al.  High Isolation and Compact Diplexer Using the Hybrid Resonators , 2010, IEEE Microwave and Wireless Components Letters.

[11]  Yong Fan,et al.  High isolation diplexer using quarter-wavelength resonator filter , 2012 .

[12]  Guangming Wang,et al.  Harmonics suppression microstrip diplexer for 3G wireless communication system using fractal‐shaped geometry , 2007 .

[13]  Ruey-Beei Wu,et al.  Microstrip diplexers design with common resonator sections for compact size, but high isolation , 2006 .

[14]  Chung-I G. Hsu,et al.  Quasi‐lumped design of UMTS diplexer using combined CPW and microstrip , 2009 .

[15]  J. Bonache,et al.  Complementary split ring resonators for microstrip diplexer design , 2005 .

[16]  Q. Chu,et al.  A Compact Open-Loop Filter With Mixed Electric and Magnetic Coupling , 2008, IEEE Transactions on Microwave Theory and Techniques.

[17]  G.-M. Wang,et al.  Diplexer using composite right-/left-handed transmission line , 2008 .