This paper presents a millimeter-wave, 60？GHz frequency band planar diplexer based on substrate integrated waveguide (SIW) technology. Diplexer consists of a pair of 5th-order SIW bandpass channel filters with center frequencies at 59.8？GHz and 62.2？GHz providing 1.67% and 1.6% relative bandwidths, respectively. SIW-to-microstrip transitions at diplexer ports enable integration in a millimeter-wave transceiver front end. Measurements are in good agreement with electromagnetic simulation, reporting very good channel isolation, small return losses, and moderate insertion losses in the passbands. The proposed SIW planar diplexer is integrated into a millimeter-wave transceiver front end for 60？GHz point-to-point multigigabit wireless backhaul applications, providing high isolation between transmit and receive channels. 1. Introduction The deployment of millimeter-wave integration technologies is critical for the wireless systems evolution. A variety of applications have been recently proposed in the frequency range between 60？GHz and 94？GHz including wireless networks [1], automotive radars [2], imaging sensors [3], and biomedical devices [4]. These systems require cost-effective technologies suitable for mass production and high density integration techniques, combined with a low-cost fabrication process. Substrate Integrated Waveguide (SIW) technology [5–8] is a promising candidate for providing compact, flexible, and cost-effective millimeter-wave circuits and systems which preserve most of the advantages of the conventional metallic waveguides, namely, complete shielding, low loss, high-quality factor, and high power handling capability [9]. Most of the classical passive components have been implemented in SIW technology. This solution usually permits to obtain components with a substantial reduction in size; moreover, the losses are lower than in the corresponding microstrip devices especially in the millimeter-wave frequency range, and there are no radiation and packaging problems. In the literature, SIW filters have received a particular attention. Focusing on the 60？GHz frequency band, in [10] a four-pole 60？GHz SIW bandpass filter has been modeled, while in [11] a 60？GHz SIW quasi-elliptic filter has been designed and fabricated. The diplexer is one of the key components in a transceiver front end and greatly affects system’s performance acting as channel separator. This becomes evident in the frequency division duplex systems where frequency separation between transmit and receive chains needs to be provided. Diplexer design is usually based on
References
[1]
R. C. Daniels and R. W. Heath, “60？GHz wireless communications: emerging requirements and design recommendations,” IEEE Vehicular Technology Magazine, vol. 2, no. 3, pp. 41–50, 2007.
[2]
W. J. Fleming, “New automotive sensors–a review,” IEEE Sensors Journal, vol. 8, no. 11, pp. 1900–1921, 2008.
[3]
L. Yujiri, M. Shoucri, and P. Moffa, “Passive millimeter wave imaging,” IEEE Microwave Magazine, vol. 4, no. 3, pp. 39–50, 2003.
[4]
K. Mizuno, Y. Wagatsuma, H. Warashina et al., “Millimeter-wave imaging technologies and their applications,” in Proceedings of the 8th IEEE International Vacuum Electronics Conference (IVEC '07), pp. 13–14, May 2007.
[5]
U. Hiroshi, T. Takeshi, and M. Fujil, “Development of a ‘laminated waveguide’,” IEEE Transactions on Microwave Theory and Techniques, vol. 46, no. 12, pp. 2438–2443, 1998.
[6]
D. Deslandes and K. Wu, “Single-substrate integration technique of planar circuits and waveguide filters,” IEEE Transactions on Microwave Theory and Techniques, vol. 51, no. 2, pp. 593–596, 2003.
[7]
F. Xu and K. Wu, “Guided-wave and leakage characteristics of substrate integrated waveguide,” IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 1, pp. 66–72, 2005.
[8]
D. Deslandes and K. Wu, “Accurate modeling, wave mechanisms, and design considerations of a substrate integrated waveguide,” IEEE Transactions on Microwave Theory and Techniques, vol. 54, no. 6, pp. 2516–2526, 2006.
[9]
M. Bozzi, L. Perregrini, K. Wu, and P. Arcioni, “Current and future research trends in substrate integrated waveguide technology,” Radioengineering, vol. 18, no. 2, pp. 201–209, 2009.
[10]
F. Mira, A. A. San Blast, V. E. Boria, and B. Gimeno, “Fast and accurate analysis and design of Substrate Integrated Waveguide (SIW) filters,” in Proceedings of the 37th European Microwave Conference (EUMC '07), pp. 170–173, October 2007.
[11]
G. H. Lee, C. S. Yoo, J. G. Yook, and J. C. Kim, “SIW (Substrate Integrated Waveguide) quasi-elliptic filter based on LTCC for 60-GHz application,” in Proceedings of the 4th European Microwave Integrated Circuits Conference (EuMIC '09), pp. 204–207, October 2009.
[12]
A. Morini and T. Rozzi, “Analysis of compact E-plane diplexers in rectangular waveguide,” IEEE Transactions on Microwave Theory and Techniques, vol. 43, no. 8, pp. 1834–1839, 1995.
[13]
J. Dittloff and F. Arndt, “Computer-aided design of slit-coupled H-plane T-junction diplexers with E-plane metal-insert filters,” IEEE Transactions on Microwave Theory and Techniques, vol. 36, no. 12, pp. 1833–1840, 1988.
[14]
E. Ofli, R. Vahldieck, and S. Amari, “Novel E-plane filters and diplexers with elliptic response for millimeter-wave applications,” IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 3, pp. 843–851, 2005.
[15]
Z. C. Hao, W. Hong, X. P. Chen, J. X. Chen, and K. Wu, “Planar diplexer for microwave integrated circuits,” Microwaves, Antennas and Propagation, IEE Proceedings, vol. 152, no. 6, pp. 455–459, 2005.
[16]
H. J. Tang, W. Hong, J. X. Chen, G. Q. Luo, and K. Wu, “Development of millimeter-wave planar diplexers based on complementary characters of dual-mode substrate integrated waveguide filters with circular and elliptic cavities,” IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 4, pp. 776–782, 2007.
[17]
S. H. Han, X. L. Wang, Y. Fan, Z. Q. Yang, and Z. N. He, “The generalized chebyshev substrate integrated waveguide diplexer,” Progress in Electromagnetics Research, vol. 73, pp. 29–38, 2007.
[18]
Y. Dong and T. Itoh, “Substrate integrated waveguide loaded by complementary split-ring resonators for miniaturized diplexer design,” IEEE Microwave and Wireless Components Letters, vol. 21, no. 1, pp. 10–12, 2011.
[19]
N. Athanasopoulos, D. Makris, and K. Voudouris, “5th order millimeter-wave substrate integrated waveguide band pass filters,” in Proceedings of the IEEE International Conference on Electromagnetics in Advanced Applications (ICEAA '11), pp. 98–101, September 2011.
[20]
N. Athanasopoulos, D. Makris, and K. Voudouris, “Development of a 60？GHz Substrate Integrated Waveguide planar diplexer,” in Proceedings of the IEEE-MTT-S International Microwave Workshop Series on Millimeter Wave Integration Technologies, pp. 691–694, 2011.
[21]
D. Deslandes and K. Wu, “Design consideration and performance analysis of Substrate Integrated Waveguide components,” in Proceedings of the 32nd European Microwave Conference, pp. 1–4, September 2002.
[22]
G. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters, Impendence-Matching Networks, and Coupling Structures, Artech House, Norwood, NJ, USA, 1980.
