In this paper, a new type of microwave microfluidic sensor is proposed to detect and determine the dielectric properties of common liquids. The technique is based on perturbation theory, in which the resonant frequency and quality factor of the microwave resonator depend on the dielectric properties of the resonator. A microstrip split-ring resonator with two gaps is adopted for the design of the sensors (i.e., a double split-ring resonator). This resonator is both compact and planar, making it suitable for a lab-on-a-chip approach. Several types of solvents are tested with two types of capillaries to verify sensor performance. At 3 GHz, very good agreement is demonstrated between simulated and measured results.

Novel Microwave Microfluidic Sensor Using a Microstrip Split-Ring Resonator

This paper reports on a new topology of high-performance dual-band filters. This topology is derived from the Dual Behavior Resonator (DBR) filter. The resulting resonator is directly dual-band. It allows the control of two bandpasses separated by a transmission zero to ensure a high rejection level between them. Moreover, two other transmission zeros are located on either side of the two bandpasses. The possibilities offered by this structure are discussed and measurements are presented to validate the method.

An original topology of dual-band filter with transmission zeros

This paper presents a comprehensive critical overview of fundamental and practical aspects of the modern stripline broadband ferromagnetic resonance (BFMR) spectroscopy largely employed for the characterisation of magnetic low-dimensional systems, such as thin ferro- and ferromagnetic, multiferroic and half-metallic films, multi-layers and nanostructures. These planar materials form the platform of the nascent fields of magnonics and spintronics. Experimental and theoretical results of research on these materials are summarised, along with systematic description of various phenomena associated with the peculiarities of the stripline BFMR, such as the geometry of stripline transducers, the orientation of the static magnetic field, the presence of microwave eddy currents, and the impacts of non-magnetic layers, interfaces and surfaces in the samples. Results from 240 articles, textbooks and technical reports are presented and many practical examples are discussed in detail. This review will be of interest to both general physical audience and specialists conducting research on various aspects of magnetisation dynamics and nanomagnetism.

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Broadband stripline ferromagnetic resonance spectroscopy of ferromagnetic films, multilayers and nanostructures

In this article, grey-box and black-box surrogate modeling are described, with some key findings. The important point is that surrogate modeling has a solid mathematical basis leading to what has become a dramatic increase in our ability to develop engineering models and to engineer systems. In Section 2, a systematic approach to constructing surrogate models is provided. Each step is explained using published methods. Section 3 presents surrogate modeling examples from the domain of circuits and systems.

Demystifying Surrogate Modeling for Circuits and Systems

In this paper, a class of dual-band ring-resonator bandpass filters is proposed based on a single ring resonator. As its most distinctive feature, two pairs of first- and second-order degenerate resonant modes in a ring resonator are simultaneously excited, resulting in a compact dual-mode dual-band bandpass filter with two transmission poles in both passbands. Firstly, two capacitors or parallel-coupled lines are placed at two nonorthogonally excited positions along a ring resonator in order to excite the two first-order degenerate modes and create multiple transmission zeros. Next, a set of perturbations is introduced on the ring to excite the two second-order degenerate modes. In our design, two excitation positions are first placed with between 45°- and 135°-separation on a ring. Simulations show that, with a proper arrangement of the excitation angle, two transmission poles in the first passband can be excited and more transmission zeros can be generated. Four and eight open-circuited stubs are loaded symmetrically along the ring, resulting in synchronous excitation of two poles in the second passband. Of the two designed filters with 135°- and 45°-separation, the one with 45° exhibits much better out-of-band performance with three additional transmission zeros at frequencies lower than the first passband, between the two passbands and higher than the second passband. Finally, two filter prototypes are fabricated and their measured results are found to be in good agreement with theory.

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A Dual-Band Ring-Resonator Bandpass Filter Based on Two Pairs of Degenerate Modes

This paper deals with a dual-mode ring resonator fed by quarter-wavelength side-coupled lines. The resonator synthesis was developed so as to fix the central frequency, bandwidth, and transmission zeros frequencies, as well as the insertion loss in the passband. Based on this resonator, several bandpass filters were designed, which include the cascaded rings and the combination of such ring resonator with coupled line sections. Simulations are proposed throughout the paper to illustrate the various possibilities offered by the concept. The filters' experimental results in microstrip technology are also presented to validate the idea.

Quarter-Wavelength Side-Coupled Ring Resonator for Bandpass Filters

This paper presents the results of the fabrication and characterization up to 220 GHz, of thin-film microstrip (TFMS) transmission-line structures. The transmission lines are fabricated on a low-resistivity silicon substrate (/spl rho/=10 /spl Omega/ /spl middot/ cm). TFMS lines with a thick dielectric layer (20 /spl mu/m of benzocyclobutene is used here) present losses of 0.3 dB/mm at 94 GHz and 0.6 dB/mm at 220 GHz. Thus, using this technology, it will be possible to develop monolithic microwave integrated circuits on a silicon substrate.

Fabrication and characterization of low-loss TFMS on silicon substrate up to 220 GHz

This paper discusses a method used to design planar bandpass filters for millimeter-wave applications in U- and W-band frequency ranges. For technical reasons, these filters have to be implemented on silicon-based technology. So as to decrease the insertion losses levels inherent in silicon substrate, we propose a thin-film microstrip-like technology implemented on a benzocyclobutene layer. In addition, a dual-behavior resonator-based filter topology enabled us to fit a hardened specification. In association with this new topology, we employed an automated design procedure that combines both circuit and full-wave simulations. It is based on a statistical sensitivity study performed by design-of-experiment analysis.

Design of narrow-band DBR planar filters in Si-BCB technology for millimeter-wave applications

This paper deals with the design of passive coplanar devices in the W-frequency band. As long as coplanar transmission lines are correctly dimensioned, analytical models based on quasi-TEM approximation can be used. Such models are associated with a correct definition of the reference planes at the junctions and employed for junction discontinuities, T- and cross-junctions. In order to validate these assertions, simulated and experimental data on classical quarter-wavelength shunt-stub filters are first presented. Then the design of traditional coupled-line filters is examined. The problems in terms of insertion loss associated with these kinds of narrow-band applications are discussed here. Minimization of insertion losses requires increasing the width of the strips. Consequently, the design becomes complex and modeling using transmission-line models less accurate. Nevertheless, as an optimization procedure is needed to tune the filter theoretically, such a very fast design method is necessary. Simulated and experimental results in the range 500 MHz to 110 GHz are compared throughout the paper.

Wide- and narrow-band bandpass coplanar filters in the W-frequency band

This article deals with the design of dual-mode ring resonator fed by quarter wavelength coupled-lines and its applications for bandpass filters. A specific synthesis was developed for ring-based resonator which made ease the design of further bandpass filters. Three compact bandpass filters were designed at 2 GHz. Comparison between experiments and simulated results proved both synthesis accuracy and QSCR-based filters efficiency toward electrical performances and size reduction. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 307–312, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23067

Gaetan Prigent

Papers

Quarter-Wavelength Side-Coupled Ring Resonator for Bandpass Filters

Fabrication and characterization of low-loss TFMS on silicon substrate up to 220 GHz

Design of narrow-band DBR planar filters in Si-BCB technology for millimeter-wave applications

Wide- and narrow-band bandpass coplanar filters in the W-frequency band

Synthesis of quarter wavelength side-coupled ring (qscr) resonator—applications to bandpass filters design