Novel empty substrate integrated waveguide for high performance microwave integrated circuits

"(c) 20xx 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."Abstract Over the last years, a great number of substrate integrated circuits has been developed. These new circuits are a compromise between the advantages of classical waveguide technologies, such as high quality factor and low losses, and the advantages of planar circuits, such as low cost and easy compact integration. Although their quality factor and losses are better than for planar circuits, these characteristics are worse than in the case of waveguides, mainly due to the presence of the dielectric substrate. In order to improve the performance of the integrated circuits, a new methodology for manufacturing empty waveguides, without a dielectric substrate, but at the same time completely integrated in a planar substrate, is proposed in this work. A wideband transition with return losses greater than 20 dB in the whole bandwith of the waveguide allows the integration of the empty waveguide into the planar substrate so that the waveguide can be directly accessed with a microstrip line. Therefore, a microwave circuit integrated in a planar substrate, but at the same time with a very high quality factor (measured quality factor is 4.5 times higher than for the same filter in the substrate integrated waveguide), and very low losses is successfully achieved.This work was supported by the Ministerio de Ciencia e Innovacion, Spanish Goverment, under Research Project TEC2010-21520-C04-03 and Research Project EC2010-21520-C04-01, and by the Autonomous Government of Castilla-La Mancha under Research Project PPII10-0047-0220.Belenguer Martínez, Á.; Esteban González, H.; Boria Esbert, VE. (2014). Novel empty substrate integrated waveguide for high performance microwave integrated circuits. IEEE Transactions on Microwave Theory and Techniques. 62(4):832-839. https://doi.org/10.1109/TMTT.2014.2309637S83283962

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

Distributed Models for Filter Synthesis

The limitations of filter synthesis methods based on classic equivalent circuits with the enhanced distributed models and synthesis procedures able to overcome such limitations are presented. A modified procedure that corrects the waveguide lengths has been proposed. The input and output reflection coefficients of the ideal prototype steps are real. The shunt capacitive effect introduces a phase shift in the reflection coefficients of each waveguide step. The representation of the filter structure can be improved if the waveguide steps are analyzed with a full-wave electromagnetic (EM) simulator, and their responses are stored in the form of ABCD matrices. The desired filter passband cutoff frequency was 11 GHz, with a specified return loss of 25 dB, and a gap height greater than 4.25 mm. High-power applications with wide stopbands often require impractical waveguide sections. The accurate EM simulators are used to find an almost exact equivalence between the prototype and the filter parts.Boria Esbert, VE.; Soto Pacheco, P.; Cogollos Borras, S. (2011). Distributed Models for Filter Synthesis. IEEE Microwave Magazine. 12(6):87-100. doi:10.1109/MMM.2011.942010S8710012

Analysis and design of re-configurable combline filters using dielectric tuners

[EN] This article describes different tunable structures for typical waveguide combline filters. In this context, several configurations using dielectric tuners have been studied for resonators, inter-resonator couplings, and input/output couplings. All configurations are analyzed in a wide frequency range showing advantages and drawbacks. Using the best structures in terms of performance, a fully re-configurable filter has been designed. The filter provides a wide tuning range in terms of center frequency while maintaining a high Q factor, and a constant bandwidth and return losses. A first filter prototype has been designed at L-band. The structure demonstrates a tunability in terms of frequency range of about 400 %, thereby clearly demonstrating that the approach we propose is indeed a very promising candidate for implementing tunable combline filters based on dielectric tuners.Sharma, A.; Cogollos, S.; Boria Esbert, VE.; Guglielmi, M. (2022). Analysis and design of re-configurable combline filters using dielectric tuners. IEEE. 122-125. https://doi.org/10.23919/EuMC50147.2022.978434512212

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

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

A New Family of Multiband Waveguide Filters Based on a Folded Topology

[EN] In this article, we describe a new family of multiband waveguide filters based on a folded topology. The folded topology allows to use the filters of different orders and the introduction of transmission zeros. The design of the multiband filter is based on the aggressive space mapping (ASM) technique and is able to take into account manufacturing details, such as round corners and tuning elements. The filter structure is validated by designing, manufacturing, and measuring a triband filter. The agreement between simulations and measurements is shown to be excellent, thereby fully validating both the filter topology and the design process.This work was supported in part by the La Caixa Foundation under Grant B004442 and in part by the Agencia Estatal de Investigacion (AEI) and Union Europea through the Fondo Europeo de Desarrollo Regional (FEDER) "Una manera de hacer Europa" (AEI/FEDER, UE) under Research Project TEC2016-75934-C4-1-R.Melgarejo, JC.; Cogollos, S.; Guglielmi, M.; Boria Esbert, VE. (2020). A New Family of Multiband Waveguide Filters Based on a Folded Topology. IEEE Transactions on Microwave Theory and Techniques. 68(7):2590-2600. https://doi.org/10.1109/TMTT.2020.2989111S2590260068

Multipactor discharges in parallel-plate dielectric-loaded waveguides including space-charge effects

[EN] The objective of this paper is to study the time evolution of multipactor discharges in a parallel-plate dielectric-loaded waveguide. The electron discharge phenomena investigated in this paper include the effects of space charge, as well as the presence of time varying static fields. In order to perform the simulations presented in this paper, an approach considering simultaneously multiple effective electrons has been used. The results obtained demonstrate that multipactor discharges do turn off by themselves under certain circumstances when they occur in such dielectric-loaded structures.This work was supported by the Spanish Government's Ministerio de Educacion y Ciencia under Project TEC2007-67630-C03-01. The review of this paper was arranged by Editor W. Menninger.Coves, A.; Torregrosa-Penalva, G.; Vicente, C.; Gimeno, B.; Boria Esbert, VE. (2008). Multipactor discharges in parallel-plate dielectric-loaded waveguides including space-charge effects. IEEE Transactions on Electron Devices. 55(9):2505-2511. https://doi.org/10.1109/TED.2008.927945S2505251155

Space Qualification of Metalized Additive Manufactured Filters

[EN] The space industry is seeking new solutions for the development of lightweight, inexpensive and easy-to-manufacture on-board communication payload devices. One of the proposed technologies is additive manufacturing (AM) of polymeric materials that are subsequently metallized. The devices developed using this technique must be operational in the particular space environment conditions. In this work we study the integrity of filters made by additive manufacturing against the extreme conditions of mechanical stress, temperature and power management as described in the standard of the European Space Agency (ESA) for satellite payload. To carry out this qualification for space, two types of X-band filters with identical frequency responses have been designed and manufactured: a classic H-plane waveguide cavities filter, and three filters on surface-mount technology (SMT). Two of the SMT filters are low height rectangular cavities filters, while the third one is a high circular cavities filter. This selection was intended to verify that the AM technique offered good results regardless of the devices topology. Two mechanical vibration tests were performed: sinusoidal sweep and random vibration. These tests emulate the transport and launching conditions of the satellite payload. Furthermore, it was measured the mechanical natural frequency of the filters, and its variation after being exposed to the tests in order to evaluate their physical integrity. The thermal analysis was performed emulating the temperature profile experienced by the satellite payload during working conditions. Then, the power handling tests were carried out. The secondary electron emission yield of the material (metallized polymer) was firstly measured. The power levels, location and frequency at which a multipactor discharge would occur were analyzed for both, low-height and standard-height, filters. Finally, both filters were subjected to those power levels, under high vacuum conditions, to check if the said multipactor discharges occurred. The mechanical stress and temperature tests prove that the developed filters can survive the hard launching and operation conditions of commercial satellite payloads. The multipactor tests report the high power levels that the devices can handle without risk of radiofrequency (RF) breakage. All these tests allow to fully qualify the proposed manufacturing technique for spatial applications.This work was supported in part by the Agencia Valenciana de la Innovacion Research Project under Grant INNVA1/2020/84; in part by the Agencia Estatal de Investigacion, Spain, through the Fellowship for Training PhDs under Grant BES-2017-079728; and in part by the Ministerio de Ciencia e Innovacion (MICIN), Spanish Government through the Research and Development Project PID2019-103982RB-C41 under Grant MICIN/AEI/10.13039/501100011033.Bachiller Martin, MC.; Nova-Giménez, V.; Ferrer, Á.; Boria Esbert, VE. (2022). Space Qualification of Metalized Additive Manufactured Filters. IEEE Access. 10:96952-96966. https://doi.org/10.1109/ACCESS.2022.320540896952969661

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