Substrate Integrated Coaxial Line Planar Transitions to Single-Layer Transmission Lines and Waveguides

This paper presents inline transitions from substrate integrated coaxial line (SICL) to microstrip line, coplanar waveguide (CPW), as well as substrate integrated waveguide (SIW). A common property is the conversion of transmission medium from double to single substrate layer of PCB. The first two of described transitions can be used from DC up to the presence of higher order modes if the characteristic impedances of two meeting transmission lines are matched. The transition to substrate integrated waveguide is of higher complexity, yet compact. Both sides of the SICL-SIW transition are strongly coupled to resonant cavity, and return loss greater than 20 dB is achieved in fractional bandwidth of 10.91 %. Improvements compared to the existing solutions have been made in designs of all three transitions

A Fully Planar Substrate Integrated Probe-Based Wideband Orthomode Transducer

This paper introduces a planar orthomode transducer (OMT) using substrate integrated waveguides (SIWs) and substrate integrated coaxial lines (SICLs) that is entirely contained within two substrate layers. SICLs form a quadruplet of probes inside the metal waveguide with fully symmetrical geometry. Such a structure is smaller and lighter than a waveguide OMT, its construction is simpler than of a coaxial OMT, however, isolation and loss properties are less degraded compared to the use of planar unshielded technologies such as microstrip. A new wideband inline SICL to SIW transition has been developed to allow grade separation of SIWs belonging to opposite polarizations through different substrate layers. The designed substrate integrated probe-based OMT on RO4003CTM substrate covers the frequency band from 8.1 to 12.5 GHz with return loss higher than 19 dB, insertion loss less than 1.2 dB, inter-port isolation higher than 62 dB and cross-polarization discrimination higher than 65 dB

High-Performance Coplanar Waveguide to Empty Substrate Integrated Coaxial Line Transition

Recently, a new empty coaxial structure, entirely built with printed circuit boards, has been proposed. The resulting coaxial line has low radiation, low losses, high-quality factor, and is nondispersive. Up to now, this coaxial line has not been completely integrated in a planar substrate, since a working transition to a traditional planar line has not been defined yet. Therefore, in this paper, a high-quality transition from coplanar waveguide to this new empty coaxial line is proposed. With this transition, the coaxial line is completely integrated in a planar circuit board, so that it truly becomes an empty substrate-integrated coaxial line. The proposed transition has been fabricated. Both full-wave simulated and measured results show an excellent agreement. Therefore, the proposed transition is suitable to develop completely substrate-integrated components for applications in wideband communication systems that require very high quality responses and protection from external interferences. To show this fact, this new transition has been applied to integrate a high-performance empty coaxial filter in a planar substrate. The measured response of this filter is excellent, and proves the goodness of the proposed transition that has enabled, for the first time, the complete integration of an empty coaxial line in a planar substrate.This work was supported by the Ministerio de Economia y Competitividad, Spanish Goverment under Research Projects TEC2013-47037-C5-3-R and TEC2013-47037-C5-1-R.Belenguer Martínez, Á.; Borja, A.; Esteban González, H.; Boria Esbert, VE. (2015). High-Performance Coplanar Waveguide to Empty Substrate Integrated Coaxial Line Transition. IEEE Transactions on Microwave Theory and Techniques. 63(12):4027-4034. doi:10.1109/TMTT.2015.2496271S40274034631

Multiport beamforming system based on reconfigurable waveguide phased antenna array for satellite communication applications

A multiport K/Ka-band beamforming system based on the reconfigurable waveguide phased antenna array is presented in this thesis. The waveguide structure is used to achieve low loss, wideband performance, and simple installation and maintenance. The antenna array is adopted to compensate for the high propagation loss in higher frequency, which also provided flexible functions for multi-user wireless communication applications. The reconfigurable waveguide transitions are the most crucial component in this beamforming system to achieve dual linear-polarized/left-handed circular-polarized/right-handed circular-polarized functions at K/Ka-band respectively by using the reconfigurable structure. It provided much better performance in bandwidth compared with the recent dual-band/dual-mode waveguide transitions. The waveguide antenna and antenna arrays are reconfigurable and replaceable to meet the design purposes and requirements for linear-polarized/left-handed circular-polarized/right-handed circular-polarized functions. The ultra-bandwidth from K-band to Ka-band provided advantages in saving cost and flexible functions due to the waveguide antenna array parts being applicable for both transmitting/receiving systems for K/Ka-band. This advanced beamforming system could provide many merits such as low loss, wideband, compact structure, high functional flexibility, lower cost, simpler installation, and easier maintenance by using the waveguide reconfigurable. These advantages are indicated by the sufficiently good performance in both the simulated and measured results in this thesis, which demonstrated that this beamforming system design is applicable for wireless communication applications in high frequency, especially for satellite communication applications with separated unlink and downlink systems. The potential and prospect for a MIMO beamforming system with a multilayer PCB feeding network are also demonstrated from the wideband performance of multilayer SICL power divider and SICL-to-waveguide transitions in this thesis to get a more flexible structure for a MIMO beamforming system and more compact structure

Miniaturization of Power Divider and 90º Hybrid Directional Coupler for C-Band Applications Using Empty Substrate-Integrated Coaxial Lines

(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] This paper presents the practical realization of a power divider and a 90° hybrid directional coupler in an empty substrate-integrated coaxial line (ESICL) for C-band frequency applications. This new type of transmission line is very promising in terms of electric performance, bandwidth, integration with other planar circuits, and manufacturing simplicity. The ESICL has been designed for obtaining a wide monomode bandwidth with a characteristic impedance of 50 . Furthermore, an improvement of the efficient transition between the ESICL and the grounded coplanar waveguide, used as feeding line, has been also proposed. The passive devices built using this technology are reduced in mass and volume, keeping robustness, and providing a well-balanced power division, as well as reduced losses and high isolation in the whole operational bandwidth. Two prototypes have been manufactured and the experimental results are in good agreement with the simulated designs.This work was supported in part by the Generalitat Valenciana Research under Project PROMETEOII/2015/005, in part by the Ministerio de Educacion, Cultura y Deporte, Spain, through the Fellowship Program for Training University Professors under Grant FPU14/00150, and in part by the Ministerio de Economia y Competitividad, Spain, through the Research and Development Projects under Grant TEC2016-75934-C4-1-R and Grant TEC2016-75934-C4-3-R.Merello-Gimenez, JM.; Nova-Giménez, V.; Bachiller Martin, MC.; Sánchez-Marín, JR.; Belenguer Martínez, Á.; Boria Esbert, VE. (2018). Miniaturization of Power Divider and 90º Hybrid Directional Coupler for C-Band Applications Using Empty Substrate-Integrated Coaxial Lines. IEEE Transactions on Microwave Theory and Techniques. 66(6):3055-3062. https://doi.org/10.1109/TMTT.2018.2828089S3055306266

Stop Band Continuous Profile Filter in Empty Substrate Integrated Coaxial Line

[EN] Substrate integrated waveguides reduce the losses and increase the quality factor of resonators in communication filters when compared with traditional planar technologies, while maintaining their low-cost and low-profile characteristics. Empty substrate integrated waveguides go one step further, removing the dielectric of the substrate. One of these transmission lines is the empty substrate integrated coaxial line (ESICL), which has the advantage of being a two-conductor structure. Thus, it propagates a transversal electric and magnetic (TEM) mode, which reduces the dispersion and the bandwidth limitation of other one conductor empty substrate integrated waveguides. Continuous profile filters, at the cost of being long structures, are very easy to manufacture and design (usually no optimization is needed), and they are highly insensitive to manufacturing tolerances. In this work, a simple continuous profile filter, with a stop band response, is designed for the first time using novel ESICL technology. The influence of the design parameters on the insertion losses and fractional bandwidth is discussed. A prototype has been successfully manufactured and measured. A sensitivity analysis shows the high tolerance of the proposed stop band filter to manufacturing errors.This research was funded by Ministerio de Economia, Industria y Competitividad, Spanish Government, under Research Projects TEC2016-75934-C4-3-R and TEC2016-75934-C4-1-R.Gómez, D.; Esteban González, H.; Belenguer Martínez, Á.; Boria Esbert, VE.; Lucas Borja, A. (2018). Stop Band Continuous Profile Filter in Empty Substrate Integrated Coaxial Line. Applied Sciences (Basel). 8(11):1-12. https://doi.org/10.3390/app8112176S11281

Analysis and Design of Low-Cost Waveguide Filters for Wireless Communications

The area of research of this thesis is built around advanced waveguide filter structures. Waveguide filters and the waveguide technology in general are renowned for high power capacity, low losses and excellent electromagnetic shielding. Waveguide filters are important components in fixed wireless communications as well as in satellite and radar systems. Furthermore, their advantages and utilization become even greater with increase in frequency, which is a trend in modern communication systems because upper frequency bands offer larger channel capacities. However, waveguide filters are relatively bulky and expensive. To comply with more and more demanding miniaturization and cost-cutting requirements, compactness and economical design represent some of the main contemporary focuses of interest. Approaches that are used to achieve this include use of planar inserts to build waveguide discontinuities, additive manufacturing and substrate integration. At the same time, waveguide filters still need to satisfy opposed stringent requirements like small insertion loss, high selectivity and multiband operation. Another difficulty that metal waveguide components face is integration with other circuitry, especially important when solid-state active devices are included. Thus, improvements of interconnections between waveguide and other transmission interfaces are addressed too. The thesis elaborates the following aspects of work: Further analysis and improved explanations regarding advanced waveguide filters with E-plane inserts developed by the Wireless Communications Research Group, using both cross coupled resonators and extracted pole sections (Experiments with higher filter orders, use of tuning screws, degrees of freedom in design, etc. Thorough performance comparison with competing filter technologies) - Proposing novel E-plane filter sections with I-shaped insets - Extension of the E-plane filtering structures with metal fins to new compact dual band filters with high frequency selectivity and miniaturized diplexers. - Introduction of easy-to-build waveguide filters with polymer insert frames and high-performance low-profile cavity filters, taking advantage of enhanced fabrication capabilities when using additive manufacturing - Developing new substrate integrated filters, as well as circuits used to transfer signals between different interfaces Namely, these are substrate integrated waveguide to metal waveguide planar transitions that do not require any modifications of the metal waveguides. Such novel transitions have been designed both for single and orthogonal signal polarizations

Mode Composite Waveguide for 5G and Future Wireless Communication Systems

RÉSUMÉ Dans les systèmes de communication sans fil modernes, les fonctionnalités haut-débit et multi-bande des circuits RF et micro-ondes sont de plus en plus requises dans des systèmes intégrés et compacts. La bande de fréquence actuellement utilisée pour les communications sans fil commerciales comprend les bandes aux alentours de 900 MHz, 1,9 GHz, 2,45 GHz, 3,5 GHz et 5,8 GHz pour la téléphonie mobile, l'Internet sans fil et la connectivité des capteurs. Les nouvelles bandes millimétriques comme la bande de fréquence V (57-66 GHz) et la bande E (71-76 GHz et 81-86 GHz) sont utilisées pour la connectivité des microcellules et du coeur du réseau. Le nouveau standard des communications sans fils 5G nécessite l’exploitation parallèle de bandes de fréquences, à savoir les basses et les hautes fréquences, permettant ainsi d’aller au-delà de la capacité des systèmes de communications actuels. D’une part, la demande croissante pour un meilleur débit de données nécessite une bande de fréquence beaucoup plus large, ce qui justifie le recours vers la bande de fréquences millimétriques. D'autre part, le standard LTE ainsi que les autres systèmes de communication à grande couverture doivent être développés de manière compatible avec les bandes de fréquences en bas de 6 GHz et celles qui sont au-delà de 6 GHz. Par conséquent, la mise au point de nouveaux systèmes intégrés et à bas coût capables d’opérer sur fréquences UHF et millimétriques s’avère essentielle pour le standard sans fil émergent (5G). Dans cette thèse, une nouvelle méthode de conception de circuits intégrés RF large bande et multi-bande, appelée guide d'ondes à modes composites (MCW), est proposée et étudiée. Le MCW est constitué d’une structure à double guide d'ondes interne et externe, où la structure externe agit comme une ligne coaxiale rectangulaire adaptée pour les basses fréquences, tandis que la structure interne fonctionne comme un guide d'onde rectangulaire pour les hautes fréquences, ce qui rend la structure plus simple, plus compacte et à faibles pertes d’insertion. Le MCW est susceptible de propager des signaux au sein du guide d'ondes interne suivant le mode TE10 et/ou au sein du guide d'onde externe avec le mode TEM en fonction de la fréquence, permettant ainsi d’aboutir à des performances optimales pour les deux bandes de fréquences (basse et haute). Pour ce faire, les paramètres fondamentaux du guide d'ondes et les modes d'ordre supérieur du MCW sont théoriquement étudiés.----------ABSTRACT In modern wireless communication systems, broadband and multiband functionalities of RF and microwave circuits are often required in a highly integrated and geometrically compact front-end systems. The currently used frequency band for commercial wireless communication includes the lower bands of 900 MHz, 1.9 GHz, 2.45 GHz, 3.5 GHz and 5.8 GHz for mobile phone, wireless internet and sensor connectivity, as well as the emerging millimeter-wave (mmW) bands of V-band (57-66 GHz) and E-band (71-76 GHz and 81-86 GHz) for small cell and backhaul connectivity. The emerging 5G wireless communication system requires the deployment of both low- and high-dual frequency bands in a simultaneous manner, which should extend far beyond the capability of existing mobile communication systems. On one hand, the increasing demand for higher speed wireless data transmission requires a much larger bandwidth, where the mmW bands shall be exploited to accommodate such a bandwidth increase. On the other hand, the LTE and other long-ranged wireless platforms need to be developed in a backwards-compatible way, and it is also very important to accommodate the frequency bands below 6 GHz or sub-6-GHz frequency ranges. Therefore, the development of a low-cost and integrated hardware solution is essential for the 5G and future wireless communication systems, which should be able to support the emerging wireless deployments over an unprecedented wide UHF-to-mmW frequency range. In this thesis, the development of a broadband or multi-band hardware design platform or building technology, called mode composite waveguide (MCW), is proposed and addressed. The MCW consists of inner and outer wave-guiding duo structures, where the outer structure acts as a rectangular coaxial line suitable for lower frequency operation for its compact size, while the inner structure works as a rectangular waveguide suitable for higher frequency operation thanks to its simple structure and low loss. The MCW can propagate signals in the inner waveguide with TE10 mode and/or the outer waveguide with TEM mode depending on frequency to achieve optimal performance for both low and high frequency operations

Miniaturization of Power Divider and 90◦ Hybrid Directional Coupler for C-band Applications using Empty Substrate Integrated Coaxial Lines

This work presents the practical realization of a power divider and a 90◦ hybrid directional coupler in Empty Substrate Integrated Coaxial Line (ESICL) for C-band frequency applications. This new type of transmission line is very promising in terms of electric performance, bandwidth, integration with other planar circuits and manufacturing simplicity. The ESICL has been designed for obtaining a wide monomode bandwidth with a characteristic impedance of 50 ohms. Furthermore, an improvement of the efficient transition between the ESICL and the Grounded Coplanar Waveguide (GCPW), used as feeding line, has been also proposed. The passive devices built using this technology are reduced in mass and volume, keeping robustness and providing a well balanced power division, as well as reduced losses and high isolation in the whole operational bandwidth. Two prototypes have been manufactured and the experimental results are in good agreement with the simulated designs

Manufacturing Methods Based on Planar Circuits

Manufacture of hybrid 3D-planar circuits, especially those incorporating empty waveguides on substrates, can benefit from most standardized planar fabrication processes, although they are not exactly the same. For this reason, planar circuit manufacturing methods must be adapted to the requirements of these new circuits. Through numerous fabrications and successful designs, several enhancing strategies have been established to improve all the manufacturing phases to achieve better results. They all have been proved in the following substrate-integrated technologies for the manufacturing of microwave devices: ESIW, ESICL, continuous profile, and microstrip. Thanks to these improvements, good-quality prototypes such as transitions, filters, circulators, couplers, antennas, among others, have been fabricated. Throughout the next chapter, these strategies applied along the manufacturing process will be explained: from the first manufacturing phase to the final welding of the whole circuit and taking into account external elements such as wires that may be present in these structures. For this purpose, some devices that have been published will be used as examples