Resistorless Implementation of Lossy Filters Using Coaxial SIW Resonators With Non-uniform Q

[EN] A technique for designing bandpass filters with very flat amplitude response is presented in this paper. The approach is based on the use of non-uniform-Q resonators implemented in coaxial substrate integrated waveguide (SIW) technology. An important unloaded Q-factor ratio can be obtained by adequately controlling several layout parameters of the basic resonator cell, thus enabling to optimize the in-band response of the filter. The approach is experimentally demonstrated at X-band frequencies by designing two resonators in Rogers RO4003C (¿ r = 3.55, tan ¿ = 0.0027) with unloaded Q-factors going from 53 to 270. Then, a 4th-order filter example with 2 transmission zeros is designed, fabricated and measured based on the former results. The filter is centered at 10 GHz with a 280 MHz bandwidth showing a in-band flatness better than 1 dB-pp, which would require an unloaded Q-factor about 600 for a uniform-Q implementation, therefore showing the advantages of the proposed approach for implementing bandpass filters for high-end RF and microwave applications.Marín-Martínez, S.; Martínez Pérez, JD.; Boria Esbert, VE. (2021). Resistorless Implementation of Lossy Filters Using Coaxial SIW Resonators With Non-uniform Q. IEEE. 27-29. https://doi.org/10.1109/IMFW49589.2021.9642374272

Implementing Quasi-Elliptic Microstrip Filters Using Terminating Half Sections

© 2018 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This letter presents a technique for the introduction of transmission zeros (TZs) using half section matched terminations for implementing high selectivity filters in planar technology. The proposed technique does not require any cross coupling between nonadjacent resonators or multiple signal paths, and it can be easily incorporated on any planar filter using lumped, quasi-lumped, and/or distributed elements depending on the desired response. Two different bandpass filter topologies are employed for applying the proposed technique. Both prototypes are designed, manufactured, and measured. The measured results show that the TZs can be independently located very close to the passband edges, without degrading the original filter response.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness under Grant TEC2013-48036-C3-3-R and Grant TEC2016-75934-C4-1-R.Marín-Martínez, S.; Martínez Pérez, JD.; Boria Esbert, VE. (2018). Implementing Quasi-Elliptic Microstrip Filters Using Terminating Half Sections. IEEE Microwave and Wireless Components Letters. 28(9):783-785. https://doi.org/10.1109/LMWC.2018.2855562S78378528

Design of Miniaturized Substrate Integrated Filters Using Aggressive Space Mapping

[EN] An optimization procedure for the design of miniaturized substrate integrated quasi-lumped filters based on aggressive space mapping techniques is presented in this paper. A gradient-descent approach based on a lossy coarse model is employed. Thus, a 3-pole bandpass filter response centered at 10 GHz is designed, manufactured and measured, showing the validity of the technique even if strong dependencies between the different electrical and physical parameters are present.Martínez Pérez, JD.; Sirci, S.; Boria Esbert, VE. (2019). Design of Miniaturized Substrate Integrated Filters Using Aggressive Space Mapping. IEEE. 1-4. https://doi.org/10.1109/NEMO.2019.8853742S1

A Novel Magnetic Coupling for Miniaturized Bandpass Filters in Embedded Coaxial SIW

[EN] In this paper, embedded coaxial substrate integrated waveguide (CSIW) filters with innovative magnetic couplings are presented and studied. By creating the loading capacitance of a combline topology using inner layers of a low-temperature co-fired ceramic (LTCC) stack-up, it is possible to achieve resonator miniaturization while improving the spurious-free band and providing full-packaged solutions. Moreover, a new magnetic coupling scheme consisting of short-ended stripline probes is proposed and analyzed in detail, both for direct and external couplings. An in-line three-pole filter at L-band is designed, manufactured, and measured proving how the proposed approach can be used for designing wideband bandpass filter (BPF) with extremely compact size. The designed BPF is centered at 1.5 GHz with 10% fractional bandwidth (FBW), while the layout size is just 35 x 9.5 mm(2). The experimental results validate the coaxial SIW technology that allows for, at the same time, easy integration, compact size, flexible design, and enhanced stop-band performance.This research was funded by Ministerio de Economia, Industria y Competitividad, Spanish Government, under Research Project TEC2016-75934-C4-3-R.Sirci, S.; Martínez Pérez, JD.; Boria Esbert, VE. (2019). A Novel Magnetic Coupling for Miniaturized Bandpass Filters in Embedded Coaxial SIW. Applied Sciences. 9(3):1-14. https://doi.org/10.3390/app903039411493Chen, X.-P., & Wu, K. (2014). Substrate Integrated Waveguide Filters: Practical Aspects and Design Considerations. IEEE Microwave Magazine, 15(7), 75-83. doi:10.1109/mmm.2014.2355751Rhodes, J. D. (1969). The Stepped Digital Elliptic Filter. IEEE Transactions on Microwave Theory and Techniques, 17(4), 178-184. doi:10.1109/tmtt.1969.1126929Grigoropoulos, N., Sanz-Izquierdo, B., & Young, P. R. (2005). Substrate integrated folded waveguides (SIFW) and filters. IEEE Microwave and Wireless Components Letters, 15(12), 829-831. doi:10.1109/lmwc.2005.860027Li, L., Wu, Z., Yang, K., Lai, X., & Lei, Z. (2018). A Novel Miniature Single-Layer Eighth-Mode SIW Filter With Improved Out-of-Band Rejection. IEEE Microwave and Wireless Components Letters, 28(5), 407-409. doi:10.1109/lmwc.2018.2813883Martinez, J. D., Sirci, S., Taroncher, M., & Boria, V. E. (2012). Compact CPW-Fed Combline Filter in Substrate Integrated Waveguide Technology. IEEE Microwave and Wireless Components Letters, 22(1), 7-9. doi:10.1109/lmwc.2011.2174215Nassar, S. O., & Meyer, P. (2017). Pedestal substrate integrated waveguide resonators and filters. IET Microwaves, Antennas & Propagation, 11(6), 804-810. doi:10.1049/iet-map.2016.0120Ho, M.-H., Li, J.-C., & Chen, Y.-C. (2018). Miniaturized SIW Cavity Resonator and Its Application in Filter Design. IEEE Microwave and Wireless Components Letters, 28(8), 651-653. doi:10.1109/lmwc.2018.2845101Sirci, S., Sanchez-Soriano, M. A., Martianez, J. D., Boria, V. E., Gentili, F., Bosch, W., & Sorrentino, R. (2015). Design and Multiphysics Analysis of Direct and Cross-Coupled SIW Combline Filters Using Electric and Magnetic Couplings. IEEE Transactions on Microwave Theory and Techniques, 63(12), 4341-4354. doi:10.1109/tmtt.2015.2495287Riblet, H. J. (1983). An Accurate Approximation of the Impedance of a Circular Cylinder Concentric with an External Square Tube. IEEE Transactions on Microwave Theory and Techniques, 31(10), 841-844. doi:10.1109/tmtt.1983.1131615Yang, T., Ho, K., & Rebeiz, G. M. (2014). Compact Self-Shielded 2–3 GHz High-Q Coaxial Fixed and Tunable Filters. IEEE Transactions on Microwave Theory and Techniques, 62(12), 3370-3379. doi:10.1109/tmtt.2014.236481

Microstrip Filters with Enhanced Stopband Based on Lumped Bisected Pi-Sections with Parasitics

[EN] A procedure for improving the stopband response of planar bandpass filters is presented in this letter. The technique is based on the introduction of transmission zeros by using lumpedelement bisected-pi sections at the filter input/output. As an example, a 3¿pole 10% FBW bandpass filter with Chebyshev response centered at 1 GHz, based on strongly loaded combline microstrip resonators has been designed, manufactured and measured. The proposed solution can be used on any planar topology in order to improve the stopband performance with a negligible additional footprint.This work was supported in part by MINECO (Spanish Government) under project TEC2013-48036-C3-3-R and TEC2013-47037-C5-1-R.Marín-Martínez, S.; Martínez Pérez, JD.; Valero, CI.; Boria Esbert, VE. (2017). Microstrip Filters with Enhanced Stopband Based on Lumped Bisected Pi-Sections with Parasitics. IEEE Microwave and Wireless Components Letters. 27(1):19-21. https://doi.org/10.1109/LMWC.2016.2630841S192127

Miniaturized Ultra-Wideband Bandpass Filter Based on Substrate Integrated Quasi-Lumped Resonators

[EN] A compact ultra-wideband bandpass filter employing substrate integrated quasi-lumped resonators is presented in this paper. A multi-layer hybrid structure is proposed, combining quasi-lumped resonators and surface mount components. This allows a huge miniaturization degree due to the high capacitive loading. Moreover, strong magnetic and electric couplings can be implemented thus enabling the introduction of transmission zeros for improving response selectivity. A filter example centered at 5.35 GHz with a prescribed channel bandwidth of 2.9 GHz has been designed, manufactured and measured. The filter size is smaller than 7×7 mm2. The obtained results show the feasibility of the proposed approach.This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 811232, the European Space Agency (ESA) under contract 4000124983, and the Ministerio de Ciencia e Innovación (Spanish Government) under project PID2019-103982R-C41Messaoudi, EM.; Martínez Pérez, JD.; Boria Esbert, VE. (2021). Miniaturized Ultra-Wideband Bandpass Filter Based on Substrate Integrated Quasi-Lumped Resonators. IEEE. 201-203. https://doi.org/10.1109/IMFW49589.2021.964238220120

Low Loss Tunable Filters in Substrate Integrated Waveguide

[EN] In this work, the design and experimental results of compact low-loss filters, based on the extension of the classical coaxial waveguide resonator to Substrate Integrated Waveguide technology, are successfully demonstrated. The design, fabrication and measurement of a continuously tunable cavity resonator and a two-pole filter at S-band in single-layer SIW technology are presented. These structures keep the low-cost fabrication scheme of single-layer PCB processing, while requiring less than half the area compared to a conventional SIW design.The authors would like to thank Generalitat Valenciana and MICINN (Spanish Government) for its financial support under projects GV/2009/007 and TEC2010-21520-C04-01.Sirci, S.; Martínez Pérez, JD.; Taroncher Calduch, M.; Boria Esbert, VE. (2012). Low Loss Tunable Filters in Substrate Integrated Waveguide. Waves. 1(4):69-78. http://hdl.handle.net/10251/57922S69781

Substrate Integrated Waveguide Diplexer Based on Circular Triplet Combline Filters

The design of substrate integrated waveguide (SIW) diplexers, based on combline triplet sections with transmission zeros (TZs) placed below and above the passband, is presented. In order to control the location of the TZs, positive and negative couplings are conveniently provided. A highly compact implementation based on circular substrate integrated coaxial resonators is proposed. An X band diplexer with channel center frequencies at 9.5 and 10.5 GHz and absolute bandwidths of 400 MHz is designed. The structure shows important advantages in terms of size reduction, while keeping good insertion losses as well as high rejection and isolation levels.This work was supported by MINECO (Spanish Government) under projects TEC2103-47037-C5-1-R and TEC2013-48036-C3-3-R.Sirci, S.; Martínez Pérez, JD.; Vague Cardona, JJ.; Boria Esbert, VE. (2015). Substrate Integrated Waveguide Diplexer Based on Circular Triplet Combline Filters. IEEE Microwave and Wireless Components Letters. 25(7):430-432. doi:10.1109/LMWC.2015.2427516S43043225

Novel Planar and Waveguide Implementations of Impedance Matching Networks Based on Tapered Lines Using Generalized Superellipses

(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this[EN] For the practical implementation of RF and microwave impedance matching networks, a widely employed solution¿alternative to the use of classical impedance transformers¿is based on tapered lines. This paper shows a simple method to design smooth tapers that take into account the dispersion of the line and the required design bandwidth simultaneously. A planar taper has been designed in microstrip technology with the same length of classical ones but improving their performances. A waveguide prototype has also been designed with similar performance to a commercial one but with one third of its length. Both tapered structures have been obtained through the optimization of very few parameters using the same design strategy. As a result, the reflection coefficient of the tapers can be optimally adapted to a given specific mask using the prescribed value of physical length. Experimental results for both tapers are included for the validation of the proposed topologies and the related design method.This work was supported by MINECO (Spanish Government) through R&D under Project TEC2016-75934-C4-1-R.Cogollos, S.; Vague Cardona, JJ.; Boria Esbert, VE.; Martínez Pérez, JD. (2018). Novel Planar and Waveguide Implementations of Impedance Matching Networks Based on Tapered Lines Using Generalized Superellipses. IEEE Transactions on Microwave Theory and Techniques. 66(4):1874-1884. https://doi.org/10.1109/TMTT.2018.2791952S1874188466

Advanced Filtering Solutions in Coaxial SIW Technology Based on Singlets, Cascaded Singlets, and Doublets

(c) 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] The use of singlets, cascaded singlets and doublets in coaxial substrate integrated waveguide (SIW) technology is proposed in this paper, with the aim of implementing low-loss filters with very compact size and highly-selective symmetric, asymmetric as well as dual-band responses. Singlets based on coaxial SIW resonator structures with source-load coupling are presented and studied. Then, different filter examples based on N cascaded singlets are designed, fabricated and measured at 7.5 GHz, with up to N transmission zeros (TZs) that can be easily located below and above the passband. Moreover, the application of doublets based on a dual-mode coaxial SIW resonator with source-load coupling for achieving extremely compact dual-band filters is presented, and two examples with different bandwidth configuration for each channel are designed, demonstrating the flexibility of the proposed coaxial SIW structure. The obtained experimental results of the different implemented filters show a good agreement with simulations, thus confirming the interesting potential application of these structures for the design of very compact devices with advanced filtering responses.This work was supported by the Ministerio de Economia, Industria y Competitividad, Spanish Government, under Project TEC2016-75934-C4-3-R.Sirci, S.; Sánchez-Soriano, MÁ.; Martínez Pérez, JD.; Boria Esbert, VE. (2019). Advanced Filtering Solutions in Coaxial SIW Technology Based on Singlets, Cascaded Singlets, and Doublets. IEEE Access. 7:29901-29915. https://doi.org/10.1109/ACCESS.2019.2902956S2990129915