Miniaturization of Trans-Directional Coupled Line Couplers Using Series Inductors

A miniaturized trans-directional (TRD) coupled line coupler comprises series inductors and capacitor loaded coupled lines is proposed in the paper. Series inductors are added to the periodically loaded coupled lines for further miniaturization of volume. A novel equivalent circuit is presented and theoretically analyzed. Test circuits for the miniaturized and conventional 3-dB TRD couplers were designed to operate at 1.6GHz and fabricated using printed circuit board (PCB) technology. Samples have been measured, and comparisons in terms of volume, schematic simulation results and measurement results between the miniaturized and conventional 3-dB TRD couplers have been made to validate the proposed structure. Results show that the proposed miniaturized TRD coupler achieves a size reduction of 47.6% compared to the conventional TRD coupler with similar performances.

[1]  R. W. Vogel,et al.  Analysis and design of lumped- and lumped-distributed-element directional couplers for MIC and MMIC applications , 1992 .

[2]  C. Briso-Rodriguez,et al.  Cryogenic Hybrid Coupler for Ultra-Low-Noise Radio Astronomy Balanced Amplifiers , 2009, IEEE Transactions on Microwave Theory and Techniques.

[4]  W.M. Fathelbab,et al.  Synthesis of Cul-De-Sac Filter Networks Utilizing Hybrid Couplers , 2007, IEEE Microwave and Wireless Components Letters.

[5]  Jose I. Alonso,et al.  ULTRA-BROADBAND DIRECTIONAL COUPLERS USING MICROSTRIP WITH DIELECTRIC OVERLAY IN MILLIMETER-WAVE BAND , 2011 .

[6]  R. Collin.  Foundations for microwave engineering , 1966 .

[8]  Yongshik Lee,et al.  A Design Method for Microstrip Directional Couplers Loaded With Shunt Inductors for Directivity Enhancement , 2010, IEEE Transactions on Microwave Theory and Techniques.

[9]  Qi-Zhong Liu,et al.  Reconfigurable Microstrip Patch Antenna with Switchable Polarization , 2007 .

[10]  L. Manholm,et al.  Low-loss compact Butler matrix for a microstrip antenna , 2002 .

[11]  Yi-Chyun Chiang,et al.  Design of a New Type Planar Balun by Using Trans-Directional Couplers , 2012, IEEE Transactions on Microwave Theory and Techniques.

[12]  Miguel Ferrando-Bataller,et al.  Printed Multimode Antenna for MIMO Systems , 2011 .

[13]  I.D. Robertson,et al.  Inductively Compensated Parallel Coupled Microstrip Lines and Their Applications , 2006, IEEE Transactions on Microwave Theory and Techniques.

[14]  Wen-Yan Yin,et al.  A COMPACT MICROSTRIP RAT-RACE COUPLER WITH MODIFIED LANGE AND T-SHAPED ARMS , 2011 .

[15]  Yi-Chyun Chiang,et al.  Transdirectional Coupled-Line Couplers Implemented by Periodical Shunt Capacitors , 2009, IEEE Transactions on Microwave Theory and Techniques.

[16]  Jui-Ching Cheng,et al.  DESIGN OF CMOS QUADRATURE VCO USING ON- CHIP TRANS-DIRECTIONAL COUPLERS , 2010 .