A Three-Pole Substrate Integrated Waveguide Bandpass Filter Using New Coupling Scheme

A novel three-pole substrate integrated waveguide (SIW) bandpass filter (BPF) using new coupling scheme is proposed in this paper. Two high order degenerate modes (TE102 and TE201) of a square SIW cavity and a dominant mode (TE101) of a rectangular SIW cavity are coupled to form a three-pole SIW BPF. The coupling scheme of the structure is given and analyzed. Due to the coupling between two cavities, as well as the coupling between source and load, three transmission zeros are created in the stopband of the filter. The proposed three-pole SIW BPF is designed and fabricated. Good agreement between simulated and measured results verifies the validity of the design methodology well

Novel Topologies Based Rf Filtering Components And Methodologies For Wireless Communication System

Driven by the rapid progress of wireless communication technology in the past several decades, multiple generations of cellular technologies have been developed, deployed, and adopted to provide more convenient communication services to users. Nowadays, the personal hand-held devices, supporting multiple wireless standards, have been a multimedia terminal encompassing elements and functions such as video callers, Internet connectivity, home appliances remote controller, GPS, TV reception, and beyond. In order to accommodate a variety of wireless standards in a single device without imposing a substantial increase in cost and size, current and future RF transceiver front-ends should be designed with more attention. The main objective of this dissertation is to study new design topologies and implement a series of high performance RF filtering components which play critical roles in miniaturized RF transceivers supporting multiple wireless standards. A compact dual-band filter with high selectivity and wide rejection band, a filtering Wilkinson power divider, and balanced filters with fixed/reconfigurable center frequencies are proposed and successfully developed. In addition, an equation-based methodology is also first proposed and fully investigated to r

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

Design, Modelling and Implementation of Several Multi-Standard High Performance Single-Wideband and Multi-Wideband Microwave Planar Filters

The objectives of this work are to review, investigate and model the microwave planar filters of the modern wireless communication system. The recent main stream of microwave filters are classified and discussed separately. Various microwave filters with detailed applications are investigated in terms of their geometrical structures and operational performances. A comprehensive theoretical study of microwave filters is presented. The main types of microwave filters including the basic low-pass filters such as Butterworth and Chebyshev filters are fully analysed and described in detail. The transformation from low-pass prototype filters to high-pass filters, band-pass filters and band-stop filters are illustrated and introduced. Research work on stepped impedance resonator (SIR) and asymmetric stepped impedance resonator (ASIR) structure is presented. The characteristics of λg/4, λg/2 and λg (λg is the guided wavelength of the fundamental frequency in the free space) type SIR resonators, and the characteristic of asymmetric SIR resonator are categorized and investigated. Based on the content mentioned above, novel multi-standard high performance asymmetric stepped impedance resonator single-wideband and dual-wideband filters with wide stopbands are proposed. The methodologies to realize wide passband and wide stop-band filters are detailed. In addition, multi-standard high performance triplewideband, quadruple-wideband and quint-wideband filters are suggested and studied. The measurement results for all prototype filters agree well with the theoretical predictions and simulated results from Ansoft HFSS software. The featured broad bandwidths over single/multiple applicable frequency bands and the high performances of the proposed filters make them very promising for applications in future multistandard wireless communication

Design and analysis of miniaturized substrate integrated waveguide reconfigurable filters for mm-wave applications.

Doctoral Degree. University of KwaZulu-Natal, Durban.Microwave filters are an integral part of communication systems. With the advent of new technologies, microwave devices, such as filters, need to have superior performance in terms of power handling, selectivity, size, insertion loss etc. During the past decade, many applications have been added to the communication networks, resulting in communication systems having to operate at high frequencies in the region of THz to achieve the stringent bandwidth requirements. To achieve the requirements of the modern communication system, tunability and reconfigurability have become fundamental requirements to reduce the footprint of communication devices. However, the communication systems that are more prevalent such as planar circuits have either a large footprint or are not able to handle large amounts of power due to radiation leakage. In this thesis, Substrate Integrated Waveguide (SIW) technology has been employed. The SIW has the same properties as the conventional rectangular waveguide; hence it benefits from the high quality (Q) factor and can handle large powers with small radiation loss. The Half-mode (HMSIW), Quarter-mode (QMSIW), and Eighth-mode (EMSIW) cavity resonators have been designed and used for the miniaturization of the microwave filters. The coupling matrix method was used to implement a filter that uses cross-coupled EMSIW and HMSIW cavity resonators to improve the selectivity of the filter. Balanced circuit techniques have been used to design the circuits that preserve communication systems integrity whereby the Common Mode (CM) signal was suppressed using Deformed Ground Structure (DGS) and a center conductor patch with meandered line. For the designed dual-band filter, the common mode signal was suppressed to -90 dB and - 40 dB for the first and second passband, respectively. The insertion loss observed is 2.8 dB and 1.6 dB for the first and second passband, respectively. For tunability of the filter, a dual-band filter utilizing triangular HMSIW resonators has been designed and reconfigurability is achieved by perturbing the substrate permittivity by dielectric rods. The dielectric rods’ permittivity was changed to achieve tunability in the first instance, and then the rods’ diameter changed in the second instance. For the lowerband, frequency is tunable from 8.1 GHz to 9.15 GHz, while the upper band is tuned from 14.61 GHz to 16.10 GHz. A second order SIW filter with a two layer substrate was then designed to operate in the THz region. For reconfigurability, Graphene was sandwiched between the Silicon Di-Oxide substrate and the top gold plate of the filter, and the chemical potential of Graphene was then varied by applying a dc bias voltage. With a change in dc voltage the chemical potential of Graphene changes accordingly. From the results, a chemical potential change of 0.1 eV to 0.6 eV brings about a frequency change from 1.289 THz to 1.297 THz

Miniaturized High-Q Tunable RF Filters

This dissertation focuses on the investigation and development of novel efficient tuning techniques and the design of miniaturized high-Q tunable RF filters for high-performance reconfigurable systems and applications. First, a detailed survey of the available tuning concepts and state-of-art tunable filters is provided. Then, a novel so-called inset resonator configuration is presented for the applications of fixed and tunable coaxial filters. The design procedure of frequency tunable filters with constant absolute bandwidth (CABW) is described, and various tunable inset filters are implemented, offering many desirable merits, including the wide tuning range and stable high-Q with minimum variation. For wide octave frequency tuning ranges with CABW, a second novel concept is presented using so-called re-entrant caps tuners. Beside simplicity and compactness, this technique also features enhanced spurious performance and wider tuning capabilities than the conventional means. Also, in this dissertation, various miniaturized reconfigurable dual-band/dual-mode bandpass filters and diplexers are presented using compact dual-mode high-Q TM-mode dielectric resonators. Furthermore, a novel microfluidic-based ultra-wide frequency tuning technique for TM010-mode dielectric resonators and filters is introduced in this dissertation. In addition to the very wide tuning window, this mechanism has key advantages of low-cost, simplicity, and intrinsic switch-off. Lastly, the dissertation includes a novel bandwidth reconfiguration concept with multi-octave tuning using a single element for coaxial bandpass filters. This mechanism brings many features including the fast tuning, constant high-Q, intrinsic switch-off, and wide BW-reconfiguration

Miniaturized Dual-Band Dual-Mode TM-Mode Dielectric Filter in Planar Configuration

This paper reports a new class of compact inline dual-band bandpass filters using TM-mode dielectric resonators in planar configuration. Thanks to the employment of the dielectric-loaded TM-mode waveguide configuration and the dual-mode TM120 and TM210 resonances, substantial size miniaturization and volume saving (>70%) can be obtained in comparison with conventional waveguide technology. Additionally, the planar topology of the presented concept offers highly desirable advantages for industry and mass production including the ease of manufacturing, assembly, and tuning. Furthermore, the resonating doublets and the nonresonating TM110 mode are effectively utilized to introduce and control both inter-band and outer-band transmission zeros, advantageously increasing the isolation between the two passbands and enhancing the outer-band rejection regions. The general design procedure of the proposed filter is discussed in detail. A three-pole C-band dual-band dual-mode TM-mode dielectric filter is designed, implemented, and measured to validate the proposed configuration

Defected Ground Structure: Fundamentals, Analysis, and Applications in Modern Wireless Trends

Slots or defects integrated on the ground plane of microwave planar circuits are referred to as Defected Ground Structure. DGS is adopted as an emerging technique for improving the various parameters of microwave circuits, that is, narrow bandwidth, cross-polarization, low gain, and so forth. This paper presents an introduction and evolution of DGS and how DGS is different from former technologies: PBG and EBG. A basic concept behind the DGS technology and several theoretical techniques for analysing the Defected Ground Structure are discussed. Several applications of DGS in the field of filters, planar waveguides, amplifiers, and antennas are presented

Emerging Trends in Techniques and Technology as Applied to Filter Design

In the last decade, the filter community has innovated both design techniques and the technology used for practical implementation. In design, the philosophy has become "if you can't avoid it, use it", a very practical engineering approach. Modes previously deemed spurious are intentionally used to create in-line networks incorporating real or imaginary transmission zeros and also reduce the number of components and thus further miniaturize; spurious responses are re-routed to increase the passband width or stopband width, frequency variation in couplings is used to create complex transfer functions, with all of these developments using what was previously avoided. Clever implementations of baluns into passive and active networks is resulting in a new generation of noise-immune filters for 5G and beyond. Finally, the use of a diakoptic approach to synthesis has appeared an evolving approach in which small blocks ("singlets", "doublets", etc.) are cascaded to implement larger networks, (reducing the need for very complex synthesis), with this new approach promising a large impact on the implementation of practical structures. Filter technology has migrated towards "observe it and then adapt it", pragmatically repurposing tools not specifically originally intended for the applications. Combinations of surface wave and bulk wave resonators with L-C networks are improving the loss characteristics of filters in the region below 2 GHz. Lightweight alloys and other materials designed for spacecraft are being used in filters intended for space, to provide temperature stability without the use of heavy alloys such as Invar. Fully-enclosed waveguide is being replaced in some cases by planar and quasiplanar structures propagating quasi-waveguide modes. This is generically referred to as SIW (Substrate Integrated Waveguide). Active filters trade noise figure for insertion loss but perhaps will offer advantage in terms of size and chip-level implementation. Finally, the era of reconfiguration might be approaching, as the basic networks are evolving, perhaps lacking only the appearance of lower-loss, higher-IP solid-state tuning elements

Design and Multiphysics Analysis of Direct and Cross-Coupled SIW Combline Filters Using Electric and Magnetic Couplings

In this paper, combline substrate integrated waveguide (SIW) filters using electric and magnetic couplings are thoroughly studied. Thus, a negative coupling scheme consisting on an open-ended coplanar probe is proposed and analyzed in detail. Several in-line 3-pole filters at C-band are designed, manufactured and measured showing how the presented approach can be used for implementing direct couplings while enabling an important size reduction and improved spurious-free band compared to conventional magnetic irises. A fully-packaged quasi-elliptic 4-pole filter is also designed at 5.75 GHz showing how the negative coupling structure can be used for introducing transmission zeros by means of cross-couplings between non-adjacent resonators. Finally, average and peak power handling capabilities of these filters have been also analyzed from a multiphysics point of view. Measured results validate the theoretical predictions confirming that combline SIW filters can handle significant levels of continuous and peak power, providing at the same time easy integration, compact size and advanced filtering responses.This work was supported in part by MINECO (Spanish Government) under projects TEC2013-47037-C5-1-R and TEC2013-48036-C3-3-R. This paper is an expanded version from the IEEE MTT-S International Microwave Symposium, Phoenix, AZ, USA, May 17-22, 2015.Sirci, S.; Sánchez Soriano, MÁ.; Martínez Pérez, JD.; Boria Esbert, VE.; Gentili, F.; Boesch, 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.2015.2495287S43414354631