Fig 6. The wide band measuremen results compared with simulation response of the duplexer
The photograph of the fabricated diplexer is shown in Fig. 4, whose dimensions are 57mm×23mm×21mm (connector size is not included). In Fig. 6, the wide band response of the diplexer, there is one parasitic transmission zero of the transmitting channel, while there are two parasitic transmission zeros of the receiving channel. The parasitic transmission zeros can further enhance remote suppression. Combined with Fig. 3 and Fig. 5, we know the synthesis results, simulation results, and tested results are well matched with each other.
Conclusion: In this paper, a novel 2.6G stripline diplexer with multiple transmission zeros using frequency dependent couplings is developed. On the basis of the synthesis technique for cross-coupling filter, by introducing the frequency dependent couplings new transmission zeros are generated. The diplexer has better frequency selection characteristics, lower loss, better harmonic suppression characteristics and higher reliability, and it can be welded and integrated on the PCB board like the dielectric waveguide diplexer, it has broad application value.
Acknowledgments: This work was supported by science and technology project of Jiangxi Provincial Department of Education (GJJ2201211), key research and development plan of Ganzhou(2022B-GY9645), the natural science foundation of Jiangxi Province, China (Grant No.20202BABL201022).
2021 The Authors. Electronics Letters published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Received: xx January 2021 Accepted: xx March 2021
doi: 10.1049/ell2.10001
References
1. R. J. Cameron, Advanced coupling matrix synthesis techniques for microwave filters, IEEE Trans. Theory tech., 2003,vol.51, pp.1-10.
2. S. Tamiazzo, G. Macchiarella, Synthesis of cross-coupled filters with frequency-dependent couplings, IEEE Trans. Theory tech.,2017, vol. 65, pp. 775-782.
3. S. Amari, U. Rosenberg, Synthesis and design of novel in-line with one or two real transmission zeros, IEEE Trans. Theory tech., 2004,vol. 52, pp. 1464-1478.
4. Z. Q. Xu, P. Wang, J. X. Liao, Substrate Integrated Waveguide Filter with Mixed Coupled Modified Trisections, Electronics Letters,2013, vol. 49, pp. 482-483.
5. P. Zhao, K. Wu, Cascading fundamental building blocks with frequency-dependent couplings in microwave filters, IEEE Trans. Theory tech.,2019, vol. 67, pp. 1432-1440.
6. J. S. Hong, G. Lancaster, Microstrip filters for RF/microwave applications. John Wiley &Sons, 2004.
7. Chu, Q. X., Wang, H., A Compact Open-Loop Filter with Mixed Electric and Magnetic Coupling, IEEE Trans. Theory tech., 2008, 56, (2), pp. 431–439.
8. Szydlowski, L., Mrozowski, M., An self-equalized waveguide filter with frequency-dependent (resonant) couplings, IEEE Microw.Wireless Compon. Letter, 2014, 24, (11), pp. 769–771
9. Rong C, Xu Y, Zhang Y. Dielectric-Loaded Miniaturized Cavity Bandpass Filter with Improved Power Capacity, Electronics. 2022, 11(9):1441.
10. Ma, K., Ma ,J. G., A compact size coupling controllable filter with separate electric and magnetic coupling paths, IEEE Trans. Theory tech., 2006, 54, (3), pp. 1113–1119.
11. Zhu, F., Hong, J., Quarter-Wavelength Stepped-Impedance Resonator Filter with Mixer Electric and Magnetic Coupling, IEEE Trans. Theory tech., 2014, 24, (2), pp. 90–92.
12. Amari, S., Bornemann, J., Using frequency-dependent coupling to generate finite attenuation poles in direct-coupled resonator bandpass filters, IEEE Microw. Guided Wave Lett., 1999, 9, (10), pp. 404–406.