Air-Filled Substrate Integrated Waveguide for Low-Loss and High Power-Handling Millimeter-Wave Substrate Integrated Circuits

An air-filled substrate integrated waveguide (SIW) made of a multilayer printed circuit board process is proposed in this paper. It is of particular interest for millimeter-wave applications that generally require low cost and low-loss performance and excellent power-handling capability. This three-layered air-filled SIW allows for substantial loss reduction and power-handling capability enhancement. The top and bottom layers may make use of a low-cost standard substrate such as FR-4 on which baseband or digital circuits can be implemented so to obtain a very compact, high-performance, low-cost, and self-packaged millimeter-wave integrated system. Over Ka-band (U-band), it is shown that the air-filled SIW compared to its dielectric-filled counterparts based on Rogers substrates RT/Duroid 5880 and also 6002 reduces losses by a mean value of 0.068 dB/cm (0.098 dB/cm) and 0.104 dB/cm (0.152 dB/cm), increases average power-handling capability by 8 dB (6 dB) and 7.5 dB (5.7 dB), and quality factor by 2.7 (2.8) and 3.6 (3.8) times, respectively. The peak power-handling capability of the proposed structure is also studied. A wideband transition is presented to facilitate interconnects of the proposed air-filled SIW with dielectric-filled SIW. Design steps of this transition are detailed and its bandwidth limitation due to fabrication tolerances is theoretically examined and established. For validation purposes, a back-to-back transition operating over the Ka-band is fabricated. It achieves a return loss of better than 15 dB and an insertion loss of 0.6 ±0.2 dB ( 0.3 ±0.1 dB for the transition) from 27 to 40 GHz. Finally, two elementary circuits, namely, the T-junction and 90 ° hybrid coupler based on the air-filled SIW, are also demonstrated.

[1]  W. P. Ayres,et al.  Propagation in Dielectric Slab Loaded Rectangular Waveguide , 1958 .

[2]  E. Hammerstad,et al.  Accurate Models for Microstrip Computer-Aided Design , 1980, 1980 IEEE MTT-S International Microwave symposium Digest.

[3]  Ke Wu,et al.  Development of substrate integrated waveguide power dividers , 2003, CCECE 2003 - Canadian Conference on Electrical and Computer Engineering. Toward a Caring and Humane Technology (Cat. No.03CH37436).

[4]  Ke Wu,et al.  Single-substrate integration technique of planar circuits and waveguide filters , 2003 .

[5]  Mahmoud Shahabadi,et al.  Reduction of dielectric losses in substrate integrated waveguide , 2006 .

[6]  S. Hall,et al.  A Practical Method for Modeling PCB Transmission Lines with Conductor Surface Roughness and Wideband Dielectric Properties , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.

[7]  Ming Yu,et al.  Power-handling capability for RF filters , 2007, IEEE Microwave Magazine.

[8]  Wei Hong,et al.  Power Handling Capability of Substrate Integrated Waveguide Interconnects and Related Transmission Line Systems , 2008, IEEE Transactions on Advanced Packaging.

[9]  Chih-Jung Chen,et al.  Design of a 60-GHz Substrate Integrated Waveguide Butler Matrix—A Systematic Approach , 2010, IEEE Transactions on Microwave Theory and Techniques.

[10]  Ke Wu,et al.  Broadband phase shifter using air holes in Substrate Integrated Waveguide , 2011, 2011 IEEE MTT-S International Microwave Symposium.

[11]  Aly Fathy,et al.  A new compact wide band 8-way SIW power divider at X-band , 2011, 2011 Loughborough Antennas & Propagation Conference.

[12]  S. Safavi-Naeini,et al.  Low loss H-shape SIW hybrid coupler for millimeter-wave phased arrays antenna systems , 2012, Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation.

[13]  Ke Wu,et al.  Millimeter-wave broadband transition of substrate integrated waveguide on high-to-low dielectric constant substrates , 2013, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[14]  Jean-Marc Duchamp,et al.  Broadband transition from dielectric-filled to air-filled Substrate Integrated Waveguide for low loss and high power handling millimeter-wave Substrate Integrated Circuits , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[15]  Á. Belenguer,et al.  Novel Empty Substrate Integrated Waveguide for High-Performance Microwave Integrated Circuits , 2014, IEEE Transactions on Microwave Theory and Techniques.