In this paper, synthesis and design techniques of dual- and triple-passband filters with Chebyshev and quasi-elliptic symmetric frequency responses are proposed and demonstrated for the first time on the basis of substrate integrated waveguide technology. The inverter coupled resonator section is first investigated, and then a dual-passband Chebyshev filter, a triple-passband Chebyshev filter, and a dual-passband quasi-elliptic filter, which consist of the inverter coupled resonator sections, are synthesized from the generalized low-pass prototypes having Chebyshev or quasi-elliptic responses, respectively. Subsequently, theses filters with a symmetric response are designed and implemented using the substrate integrated waveguide scheme over the -band frequency range. The inverter coupled resonator sections composed of side-by-side horizontally oriented substrate integrated waveguide cavities are coupled, in turn, by post-wall irises. 50-Omega microstrip lines are used to directly excite the filters. Measured results are presented and compared to those simulated by Ansoft's High Frequency Structure Simulator (HFSS) software package. A good agreement between the simulated and measured results is observed, which has also validated the proposed concept of design and synthesis with the substrate integration technology.

Dual-Band and Triple-Band Substrate Integrated Waveguide Filters With Chebyshev and Quasi-Elliptic Responses

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

The electromagnetic (EM) spectrum is becoming more crowded, and it is densely populated with various wireless signals and parasitic interferers in connection with communication and sensing services. Increasingly sophisticated radio-frequency (RF), microwave, and millimeter-wave filters are required to enable the selection and/or rejection of specific frequency channels. This will occur in future generations of the wireless system, such as the current hotly debated fifth-generation communication systems, where the spectral channelization of a heterostructured wide-band signals will be critical in support of a host of coexisting bandwidths or speeds and applications. Bandpass filters have been the most useful and popular types for such applications and are the most difficult to design and develop in practice. Other types of filters such as notch (stopband) and lowpass filters have also been widely used in many systems, and their design is generally perceived less critical with respect to band-pass filters. This article will focus on the presentation and discussion of bandpass filters. Design factors or parameters of filters, such as selectivity, cost, miniaturization, sensitivity to environmental effects (temperature and humidity, for example), and power handling, combined with predefined in-band and out-of-band performance metrics, are critical specifications of the design with respect to the development of RF and microwave front ends. This is indispensable for the efficient utilization of frequency spectrum resources and the cost-effective enhancement of wireless system performances.

Substrate Integrated Waveguide Filter: Basic Design Rules and Fundamental Structure Features

This paper presents a high-performance substrate-integrated-waveguide RF microelectromechanical systems (MEMS) tunable filter for 1.2-1.6-GHz frequency range. The proposed filter is developed using packaged RF MEMS switches and utilizes a two-layer structure that effectively isolates the cavity filter from the RF MEMS switch circuitry. The two-pole filter implemented on RT/Duroid 6010LM exhibits an insertion loss of 2.2-4.1 dB and a return loss better than 15 dB for all tuning states. The relative bandwidth of the filter is 3.7 ± 0.5% over the tuning range. The measured Qu of the filter is 93-132 over the tuning range, which is the best reported Q in filters using off-the-shelf RF MEMS switches on conventional printed circuit board substrates. In addition, an upper stopband rejection better than 28 dB is obtained up to 4.0 GHz by employing low-pass filters at the bandpass filter terminals at the cost of 0.7-1.0-dB increase in the insertion loss.

A 1.2–1.6-GHz Substrate-Integrated-Waveguide RF MEMS Tunable Filter

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

We report on a new topology of coupling between substrate integrated circular cavities designed to produce particular filtering functions through combination with the classical iris-based coupling. This coupling is achieved by a grounded coplanar line etched at the top of cavities. This topology was used to realize a Ku-Band third-order filter, whose synthesis, electromagnetic simulation with HFSS, and experimental performances are presented here.

Design of a Substrate Integrated Waveguide (SIW) Filter Using a Novel Topology of Coupling

A glucose concentration sensor for microliter-volume water–glucose solutions is presented. The proposed sensor is composed of an open-loop microstrip resonator with a dielectric liquid holder (5–25- $\mu \text{L}$ volume) glued onto the gap between the line ends. The resonator is coupled to two microstrip lines forming a two-port network whose S-parameter response provide information about the dielectric properties of the liquid under study. Three versions of the sensor at resonant frequencies between 2 and 7 GHz are presented. The sensors are assessed by measuring the complex permittivity of standard liquids reported in the scientific literature. Models of the sensors are presented, which properly match the experimental results. This paper presents an experimental study of the sensors as glucose concentration retrievers. The main novelty is the use of $Q$ factor and the maximum S21 of the resonance as sensing magnitudes. The dependence of these parameters on the glucose concentration of the solutions obeys almost linear relationships. Good sensitivities have been obtained for the proposed sensors, which are coherent with previous works by other authors.

Concentration Measurement of Microliter-Volume Water–Glucose Solutions Using $Q$ Factor of Microwave Sensors

A new reconfigurable frequency cavity compatible with planar technology has been designed, manufactured and measured. An original tuning solution is proposed, based upon the insertion of vertical capacitive posts integrated within SIW cavities. One extremity of each post is connected to a floating metallic ring, located on the substrate supporting the SIW cavity. The frequency agility is obtained once the metallic ring is connected to the ground plane by short-circuited the corresponding annular slot using surface actuators. Such combination of volumetric cavity and planar activation leads to reconfigurable filters with high Q values and simplified tuning control conditions

Reconfigurable Planar SIW Cavity Resonator and Filter

This paper proposes several topologies of filters based on Substrate Integrated Circular Cavities (SICCs). SICC works on TM modes and the benefits of this technology are mainly an increased quality factor and a better design flexibility. Filters are made from cylindrical cavities integrated into a planar substrate and are fed by microstrip lines through coupling slots. Cavities are inter-coupled by irises. One-order, second-order and third-order filters are presented. Preliminary measurement data are compared to those from simulations performed with a 3-D electromagnetic structure simulator. These filters rely on the SICC concept, whose principle is explained hereafter.

Design of Ku-Band Filter based on Substrate-Integrated Circular Cavities (SICCs)

This paper reports on the application of dual behavior resonators to design triband filters. The principle is briefly presented by considering monoband, dual-band and triband filters. A circuit is proposed by using an approximate synthesis. Then, a hybrid (electromagnetic / circuit) simulation is performed to take into account the parasitic effects induced by the junction discontinuities and to allow a fast triband optimization in the same time. An example of layout with associated simulated and experimental results is proposed.

Benjamin Potelon

Papers

Design of a Substrate Integrated Waveguide (SIW) Filter Using a Novel Topology of Coupling

Concentration Measurement of Microliter-Volume Water–Glucose Solutions Using $Q$ Factor of Microwave Sensors

Reconfigurable Planar SIW Cavity Resonator and Filter

Design of Ku-Band Filter based on Substrate-Integrated Circular Cavities (SICCs)

Planar tri-band filter based on dual behavior resonator (DBR)