A Novel Planar Impedance-Transforming Tight-Coupling Coupler and Its Applications to Microstrip Baluns

A novel impedance-transforming coupled-line coupler with strong coupling coefficient is proposed in this paper. Its analytical design methodology and applications to microstrip baluns are presented. For demonstration purposes, four numerical examples of this proposed impedance-transforming coupler with different terminated impedances are given. The calculated results show that this proposed coupler not only matches two different groups of terminated impedances but also covers the total power-dividing ratio range from 0 dB to infinite value. The measured results of the fabricated coupler verify the proposed design approach. Finally, this kind of coupler is used to construct a novel planar microstrip balun. This proposed balun has many advantages including planar structure without any via holes, strong coupled lines, and wide operation bandwidth. The experimental results of this proposed balun operating at approximately 2 GHz demonstrated these proposed ideas.

[1]  Yu-Chih Hsiao,et al.  A New Broadband Marchand Balun Using Slot-Coupled Microstrip Lines , 2010, IEEE Microwave and Wireless Components Letters.

[2]  Chi-Hsueh Wang,et al.  Novel Balanced Coupled-Line Bandpass Filters With Common-Mode Noise Suppression , 2007, IEEE Transactions on Microwave Theory and Techniques.

[3]  N. Marchand,et al.  Transmission-line Conversion Transformers , 1944 .

[4]  Yu-Ting Cheng,et al.  A Miniaturized Multilayered Marchand Balun Using Coupled Artificial Transmission Lines , 2009, IEEE Microwave and Wireless Components Letters.

[5]  Yongshik Lee,et al.  Improved Capacitive Loading Method for Miniaturization of 0 dB Forward-Wave Directional Couplers , 2011, IEEE Microwave and Wireless Components Letters.

[6]  Ian D. Robertson,et al.  Analysis and design of impedance-transforming planar Marchand baluns , 2001 .

[7]  Yongle Wu,et al.  Single-Layer Microstrip High-Directivity Coupled-Line Coupler With Tight Coupling , 2013, IEEE Transactions on Microwave Theory and Techniques.

[8]  Ke-Li Wu,et al.  A Dual-Band Balun Using Partially Coupled Stepped-Impedance Coupled-Line Resonators , 2008, IEEE Transactions on Microwave Theory and Techniques.

[9]  S.Y. Zheng,et al.  Size reduced Marchand balun with integrated microstrip to CPW transition , 2010, 2010 Asia-Pacific Microwave Conference.

[10]  Wen-Yan Yin,et al.  Miniaturization of Rat-Race Coupler With Dual-Band Arbitrary Power Divisions Based on Stepped-Impedance Double-Sided Parallel-Strip Line , 2012, IEEE Transactions on Components, Packaging and Manufacturing Technology.

[11]  Xiu Yin Zhang,et al.  Compact Equal and Unequal Dual-Frequency Power Dividers Based on Composite Right-/Left-Handed Transmission Lines , 2012, IEEE Transactions on Industrial Electronics.

[12]  Yong Zhang,et al.  A Novel Ka-Band Planar Balun Using Microstrip-CPS-Microstrip Transition , 2011, IEEE Microwave and Wireless Components Letters.

[13]  Bumman Kim,et al.  Toward Integrated Circuit Size Reduction , 2008, IEEE Microwave Magazine.

[14]  Tzyh-Ghuang Ma,et al.  Miniaturized Distributed Marchand Balun Using Coupled Synthesized CPWs , 2011, IEEE Microwave and Wireless Components Letters.

[15]  R. Mongia.  RF and microwave coupled-line circuits , 1999 .

[16]  Michael Yan Wah Chia,et al.  A novel LTCC miniaturized dualband balun , 2006 .

[17]  Reyhan Baktur,et al.  Dual- and Triple-Band Wilkinson Power Dividers Based on Composite Right- and Left-Handed Transmission Lines , 2011, IEEE Transactions on Components, Packaging and Manufacturing Technology.

[18]  Sangwook Nam,et al.  New Design Formulas for Impedance-Transforming 3-dB Marchand Baluns , 2011, IEEE Transactions on Microwave Theory and Techniques.

[19]  Shao Yong Zheng,et al.  Reconfigurable RF Quadrature Patch Hybrid Coupler , 2013, IEEE Transactions on Industrial Electronics.

[20]  Yucheng Liu,et al.  Design of Compact Dual-Band Power Dividers With Frequency-Dependent Division Ratios Based on Multisection Coupled Line , 2013, IEEE Transactions on Components, Packaging and Manufacturing Technology.

[21]  Kooho Jung,et al.  Marchand Balun Embedded Probe , 2008, IEEE Transactions on Microwave Theory and Techniques.