Study of a New Planar-Type Balun Topology for Application in the Design of Balun Bandpass Filters

A comprehensive study of a new planar-type balun prototype is presented in this paper for application in the design of balun bandpass filters (BPFs) with widely used open-type resonators. The proposed balun is in general composed of two identical back-to-back quarter-wavelength (λ/4) coupled line sections. The design concept originates from the analysis of the standing wave pattern on a half-wavelength (λ/2) open-circuited transmission line. After an intuitive illustration is given, its working principle is presented to validate the feasibility of the proposed balun. Afterward, two types of the coupled line prototypes are analyzed to implement the proposed balun with filtering response, whereas a basic rule is given to realize the transmission zeros. To further demonstrate the validity of the proposed balun prototype, two practical balun BPFs with common dual-mode resonators are designed and fabricated. As expected, transmission zeros are generated near the desired passband of our presented balun filters, thereby improving their frequency selectivity. Both simulated and measured results exhibit good filtering and balun performance.

[1]  Shau-Gang Mao,et al.  Triple-Band Marchand Balun Filter Using Coupled-Line Admmittance Inverter Technique , 2013, IEEE Transactions on Microwave Theory and Techniques.

[2]  Eul-Young Jung,et al.  A Balun-BPF Using a Dual Mode Ring Resonator , 2007, IEEE Microwave and Wireless Components Letters.

[3]  Wai-Wa Choi,et al.  A Compact Microstrip Square-Loop Dual-Mode Balun-Bandpass Filter With Simultaneous Spurious Response Suppression and Differential Performance Improvement , 2011, IEEE Microwave and Wireless Components Letters.

[4]  Pei-Ling Chi,et al.  Microstrip Realization of Generalized Chebyshev Filters With Box-Like Coupling Schemes , 2007, IEEE Transactions on Microwave Theory and Techniques.

[5]  G. I. Zysman,et al.  Coupled Transmission Line Networks in an Inhomoge neous Dielectric Medium , 2017 .

[6]  Jian-Xin Chen,et al.  Design of Multilayer Balun Filter With Independently Controllable Dual Passbands , 2015, IEEE Microwave and Wireless Components Letters.

[7]  Ke-Li Wu,et al.  A Dual-Band Coupled-Line Balun Filter , 2007, IEEE Transactions on Microwave Theory and Techniques.

[8]  Sheng Sun,et al.  Compact dual-mode balun bandpass filter with improved upper stopband performance , 2011 .

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

[10]  Chu-Yu Chen,et al.  A simple and effective method for microstrip dual-band filters design , 2006, IEEE Microwave and Wireless Components Letters.

[11]  Jia-Sheng Hong,et al.  Microstrip filters for RF/microwave applications , 2001 .

[12]  W. Menzel,et al.  Novel Dual-Mode Balun Bandpass Filters Using Single Cross-Slotted Patch Resonator , 2011, IEEE Microwave and Wireless Components Letters.

[13]  Byoung Hwa Lee,et al.  A laminated balance filter using LTCC technology , 2005, 2005 Asia-Pacific Microwave Conference Proceedings.

[14]  Robert Bogdan Staszewski,et al.  Tunable Bandpass Filter With Two Adjustable Transmission Poles and Compensable Coupling , 2014, IEEE Transactions on Microwave Theory and Techniques.

[15]  Shih-Yuan Chen,et al.  Balanced-to-Unbalanced Bandpass Filters and the Antenna Application , 2008, IEEE Transactions on Microwave Theory and Techniques.

[16]  Chi-Feng Chen,et al.  Design of a Compact Microstrip Quint-Band Filter Based on the Tri-Mode Stub-Loaded Stepped-Impedance Resonators , 2012, IEEE Microwave and Wireless Components Letters.

[17]  Lei Zhu,et al.  A New Approach to Design Microstrip Wideband Balun Bandpass Filter , 2016, IEEE Microwave and Wireless Components Letters.

[18]  S. Amari,et al.  Adaptive synthesis and design of resonator filters with source/load-multiresonator coupling , 2002 .

[19]  Tao Yang,et al.  Compact Hybrid Resonator With Series and Shunt Resonances Used in Miniaturized Filters and Balun Filters , 2010, IEEE Transactions on Microwave Theory and Techniques.

[20]  C. Chen,et al.  Dual-Band Balun Bandpass Filter With Hybrid Structure , 2011, IEEE Microwave and Wireless Components Letters.

[21]  Cheng-Fu Yang,et al.  A Simple and Effective Method for Designing Frequency Adjustable Balun Diplexer With High Common-Mode Suppression , 2015, IEEE Microwave and Wireless Components Letters.

[22]  Chung-Hwa Wu,et al.  LTCC Balun Bandpass Filters Using Dual-Response Resonators , 2011, IEEE Microwave and Wireless Components Letters.

[23]  Wenquan Che,et al.  Wideband balun bandpass filter based on a differential circuit , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[24]  Kian Sen Ang,et al.  A derivation of a class of 3-port baluns from symmetrical 4-port networks , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[25]  Tao Yang,et al.  Lumped isolation circuits for improvement of matching and isolation in three-port balun band-pass filter , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[26]  Lei Zhu,et al.  Compact and High-Isolation Diplexer Using Dual-Mode Stub-Loaded Resonators , 2014, IEEE Microwave and Wireless Components Letters.

[27]  Yo-Shen Lin,et al.  Analysis and Design of New Single-to-Balanced Multicoupled Line Bandpass Filters Using Low-Temperature Co-Fired Ceramic Technology , 2008, IEEE Transactions on Microwave Theory and Techniques.