Passive microwave devices

Recent applications of CRLH unit cells used to design distributed passive and active microwave devices and circuits are presented. In particular, new configurations for small-size passive devices based on quarter-wavelength transmission line sections, as well as microwave amplifiers, oscillators and frequency doublers are analyzed. The performances of these new circuit topologies are put into evidence numerically and the results are validated by experiments.

Two important classes of passive superconductive microwave devices are described. These devices have been demonstrated using thin films of the high-temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7-x/. The devices include tapped-delay-line transversal filters with multigigahertz bandwidths and time-bandwidth products as large as 30, and narrowband (less than 3% bandwidth) microstrip filters. These devices illustrate the potential performance advantages superconductive thin films offer to the designer of a high-frequency, wide-bandwidth analog signal processing system. >

This chapter contains sections titled: Terminations Attenuators Phase Shifters Directional Couplers Hybrid Junctions Power Dividers Microwave Propagation in Ferrites Faraday Rotation Microwave Devices Employing Faraday Rotation Circulators Other Ferrite Devices This chapter contains sections titled: Problems References

[EN] The general goal of this thesis is the development of a basic tool for the analysis of passive microwave and millimetre-wave devices used in the new generation of communication systems. In particular, the work is focused on the development of a tool for an efficient and accurate modal characterization of passive devices composed of waveguides with arbitrary cross section.
\nIn order to achieve this goal, a method recently arisen and called BI-RME (Boundary Integral - Resonant Mode Expansion) is extended. This method has been revealed as one of the most appropriate, for its high computational efficiency, to characterize waveguides with arbitrary cross section. Regarding the original BI-RME method, this one will improve the precision and the efficiency of the modal solution in presence of circular and elliptic perturbations in the arbitrary waveguide contour.
\nThen, the first work consists on extending the original BI-RME method theory to circular and elliptic geometries including the possibility to connect these two new types of segments (circular and elliptic) with the straight segments used until now in the practical implementation of the method.
\nIn order to validate the new developed theory, a set of parameters as the cut-off frequencies, the cut-off wavelengths or the electromagnetic fields of canonical waveguides and arbitrarily shaped waveguides of great practical interest, are calculated. These results are compared with analytical well-known solutions or results published in the literature.
\nOnce the electromagnetic modal chart of different arbitrarily shaped waveguides is obtained, the following step is the computation of the coupling integrals between these modes and the ones of the rectangular waveguide that completely surrounds the arbitrary contour. Such integrals are essential for the modal analysis of microwave passive structures involving waveguides with arbitrary cross section.
\nFor this purpose, the new extended BI-RME method is included into a software package tool based on the integral equation method, which allows to characterize efficiently waveguide discontinuities by means of inmitance matrices (admittance or impedance). This efficient full-wave analysis method requires the knowledge of the modal chart related to all the waveguides included in the devices under consideration, as well as the coupling integrals between the modes of the two waveguides composing the discontinuity. In the rectangular waveguides case this modal information can be easily obtained in an analytical way. However, when a waveguide or both have arbitrary cross section, the accurate and efficient modal analysis can be obtained by means of the BI-RME method.
\nThe use of the integral equation method based on admittance or impedance matrices to characterize devices composed of cascading waveguides is specially advantageous because it leads to a linear system of equations. The coefficients matrix of this linear system presents a banded structure that can be appropriately exploited to increase the computational efficiency associated to the resolution of the aforementioned system, and to reduce considerably the computational cost associated to the analysis of complex devices.
\nNext step is the demonstration that in waveguides with arbitrary cross section and with one or two symmetry axes you can generate, also by means of the BI-RME method, the whole family of waveguide modes, so that they verify a certain fictitious boundary condition of electric or magnetic walls in the symmetry plane, and the advantages regarding the computation of the modes are discussed. Furthermore, those different symmetry families of waveguide modes propagate in an independent way along the structures constituted by a connection of uniform waveguides. This situation can also be exploited to increase in a remarkable way the efficiency of the Computer-Aided-Design (CAD) electromagnetic software packages.
\nOnce verified with success the efficiency and precision of the new CAD tool developed by means of the analysis of transitions published in the related technical bibliography, the analysis of really complex passive waveguide devices is performed. Some passive waveguide devices analyzed are for instance a filter with inductive coupling windows and tuning screws, a filter with rounded corners, dual mode filters in circular waveguide with elliptic irises or in elliptic waveguides, an evanescent filter, a low bandpass filter in coaxial waveguide, and finally a new 90º twist component for space applications. The simulated results are totally validated by means of comparison with other data published in the related technical bibliography, or by means of measurements of manufactured prototypes.
\nFinally, the conclusions of this work are extracted and future research lines are outlined. Publications in journal and congress presentations in the framework of this thesis are also indicated.

Active and Passive Microwave Devices and Circuits

Epitaxial TI-Ba-Ca-Cu-O films—preparation, properties and applications

This paper is about the Shielding Effectiveness (SE) measurement realized by THALES ALENIA SPACE in Toulouse on the microwave passive units and devices implemented into the communication module of the satellite payloads. In order to verify EMC design rules efficiency and the associated workmanship, these SE measurements are mandatory by the prime on all the microwave Flying Model units. Moreover, these SE measurements are also used to quantify the efficiency of the EMC design protections (Shielding gaskets or materials, interface connectors….) implemented on the RF (Radio Frequency) units during conception phase. These SE tests are performed using an oversized cavity called Mode Stirred Reverberation Chamber (MSRC) since 2007. Typical tests results and associated methodology are presented in this paper.

In this work novel behavioural features are found for the propagation and the radiation of a class of periodic structures commonly employed in various microwave passive devices and antennas. Referring in particular to an open waveguide consisting of a dielectric layer periodically modulated by a strip grating, it is shown that the low-frequency properties of the fundamental space harmonic vary as a function of the ratio of the strip width to the overall period, giving rise to unusual and initially-puzzling dispersion behaviours. We have also discovered a new complex modal solution, whose behaviour explains well both the radiative and the reactive effects in this class of structures.

Research activities at Japanese universities are reviewed placing emphasis on transmission lines for integrated circuits, filters and dielectric resonators, couplers and junctions, material constant measurements, and analytical techniques.

This work analyses original electromagnetic properties of a class of non-reciprocal components for new interesting applications in microwave and millimetre-wave passive devices and antennas. Our attention is here focused on the modal properties of basic waveguiding structures employing ferrite materials, such as the grounded slab or the non-radiative dielectric guide. The relevant full-wave spectrum of real and complex modal solutions is rigorously derived. As a result, a number of quite unusual propagation behaviours are emphasised as a function of the physical and geometrical parameters involved. Anomalous phenomena are illustrated for the dispersion curves of both proper and improper waves. Such solutions have to be deeply investigated for their physical nature and practical implications.

A method of measurement parameters of microwave devices of communication by six-port reflectometer is considered, the problem of the determination relations waves of the voltages when the signals from two generators passed through double six-port-reflectometer simultaneous influence on inputs of the measured two-port generator signals is solved.

Recent progress on metamaterials: From effective medium model to real-time information processing system

This paper presents a wafer-level integration technology of micro/millimeter-wave integrated passive devices utilizing thick photo-BCB layer as dielectrics. Maximum three layers of metal and two layers of BCB are included in the specimen. Several kinds of RF integrated passive devices (IPDs) such as microwave resonator, low-pass filter (LPF) as well as bandpass filter, are fabricated on 25um/layer thick dielectrics. The RF transmission performances are measured on wafer. The S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> and S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> of the λ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> /4 resonator are −0.774dB and −25.48dB, and the S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> and S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> of the stepped impedance resonator achieve −0.394dB and −27.42dB respectively at 24GHz. The cut-off frequency of the low pass filter is measured to be 13 GHz. The measured pass-band range of the BPF is 13.15GHz–13.75 GHz where the return loss is better than 11 dB. The pole point appears at 13.4GHz, and the return loss is 18.4dB.

In this paper, we present a low-cost, robust and high-sensitivity microwave-microfluidic sensor system based on a 11 &#x00D7; 11 arrays of symmetric composite SRR (SCSRR). The proposed microwave passive device, which operates at around 11 GHz-22GHz and is excited by a pair of patch antennas, is designed to identify different liquid samples with high permittivity, such as water-ethanol mixtures of different concentrations. Microfluidic channel is integrated into the substrate interior which improves device integration greatly. The simulated results show that the resonant frequency shift &#x25B3;f of these two resonance peaks at 13.29 GHz and 20.85 GHz is around 2.5 GHz and 6.5 GHz as the liquid samples permittivity changes from 9 to 80. The proposed metamaterial-inspired sensor has higher sensitivity and larger frequency shift &#x25B3;f on liquid samples compared with the conventional sensor reported in other literatures. As a passive device, this metamaterial-microfluidic sensor offers a potential lab-on-chip solution for liquids with high permittivity.

Particle swarm optimization (PSO) has lately become very popular in the electromagnetics domain. Although in some instances PSO shows a superior performance compared with other global optimization techniques, it is still computationally more expensive relative to classical gradient techniques. In this paper, a cooperative particle swarm optimization (CPSO) is adopted to achieve a faster convergence compared with the conventional PSO, while maintaining its main feature, which is the capability of finding global optimum. In order to deploy PSO more efficiently, the often neglected effect of the initial population on the overall convergence of PSO is discussed. It is shown that subdividing the space into grid cells and using random distribution within these cells will give the best results in terms of convergence speed. Different boundary conditions are tried on the CPSO algorithm. In order to verify the performance of the proposed algorithm, the algorithm is compared with the conventional PSO using six different objective functions. As a design example, an ultra‐wide‐band filter is designed. The results show a slightly faster convergence compared with the conventional PSO. The designed filter is fabricated and experimental results are also shown. Copyright © 2007 John Wiley &amp; Sons, Ltd.