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Microwave Theory and Techniques, IEEE Transactions on

Issue 12 • Date Dec. 2007

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Displaying Results 1 - 25 of 26
  • Table of contents

    Page(s): C1 - C4
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    Freely Available from IEEE
  • IEEE Transactions on Microwave Theory and Techniques publication information

    Page(s): C2
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    Freely Available from IEEE
  • A Wideband and Scalable Model of Spiral Inductors Using Space-Mapping Neural Network

    Page(s): 2473 - 2480
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1270 KB) |  | HTML iconHTML  

    A wideband and scalable model of RF CMOS spiral inductors by virtue of a novel space-mapping neural network (SMNN) is presented. A new modified 2-pi equivalent circuit is used for constructing the SMNN model. This new modeling approach also exploits merits of space-mapping technology. This SMNN model has much enhanced learning and generalization capabilities. In comparison with the conventional neural network and the original 2-pi model, this new SMNN model can map the input-output relationships with fewer hidden neurons and have higher reliability for generalization. As a consequence, this SMNN model can run as fast as an approximate equivalent circuit, yet preserve the accuracy of detailed electromagnetic simulations. Experiments are included to demonstrate merits and efficiency of this new approach. View full abstract»

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  • Design and Experimental Verification of Compact Frequency-Selective Surface With Quasi-Elliptic Bandpass Response

    Page(s): 2481 - 2487
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1784 KB) |  | HTML iconHTML  

    A compact frequency-selective surface (FSS) having a quasi-elliptic bandpass response is presented in this paper. This was realized by vertically cascading substrate integrated waveguide (SIW) cavities. A single SIW cavity FSS has been fully studied and approximate analytical formulas are introduced to calculate its resonant frequencies. Two different resonances can be excited by a plane wave in the single SIW cavity FSS. According to theories of the cascading cavity filter and dual-mode filter, cross coupling can be realized in cascading SIW cavity FSSs, thus a compact FSS with a quasi-elliptic bandpass response is implemented. A Ka-band sample was fabricated by a printed circuit board (PCB) process. Experiments were carried out to validate this design method. Measured results are in agreement with predicted ones. The proposed quasi-elliptic FSS presents a number of advantages, namely, high selectivity, stable performance, and much reduced volume. View full abstract»

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  • Reflection Coefficient Shaping of a 5-GHz Voltage-Tuned Oscillator for Improved Tuning

    Page(s): 2488 - 2494
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (681 KB) |  | HTML iconHTML  

    Negative resistance voltage-controlled oscillators (VCOs) are systematically designed to operate with loaded resonator networks that permit stable steady-state oscillation over a specified tuning bandwidth. Circuit parasitics, however, significantly affect tuning behavior and complicate straightforward design. This paper introduces a scheme that compensates for the effect of parasitics by introducing an embedding network that modifies the effective active device reflection coefficient and thus enables conventional one-port oscillator design techniques to be used. A common-base SiGe HBT VCO operating from 4.4 to 5.5 GHz demonstrates the technique. Phase noise is better than -85 dBc/Hz at 10-kHz offset from the carrier and the second harmonic is less than -20 dBc, while higher order harmonics are less than -40 dBc. The voltage-tuned oscillator demonstrates an oscillator figure-of-merit of at least -182 dBc/Hz over a 800-MHz tuning range. The phase-noise-bandwidth (in megahertz) product is -159 dBc/Hz. View full abstract»

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  • A Low-Loss 74–110-GHz Faraday Polarization Rotator

    Page(s): 2495 - 2501
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (835 KB) |  | HTML iconHTML  

    We have developed a switchable Faraday polarization rotator for 74-110 GHz with a typical room-temperature insertion loss of 0.6 dB and a maximum of ~1.3 dB. The device uses a cylindrical ferrite rod in the mode with an axial magnetic field applied by a solenoid. The ports are square metallic waveguides transitioning to ceramic tapers, which then couple to the ferrite rod. The device is designed for use at a temperature of 20 K, where typical loss is <0.5 dB. The design rotation is about plusmn45deg the zero-bias value, but up to 90deg is possible. The switching time is <10 s. View full abstract»

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  • Finite-Difference Time-Domain Modeling of Periodic Guided-Wave Structures and Its Application to the Analysis of Substrate Integrated Nonradiative Dielectric Waveguide

    Page(s): 2502 - 2511
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (834 KB) |  | HTML iconHTML  

    The finite-difference time-domain (FDTD) method incorporating an equivalent resonant cavity model is presented for the modeling and analysis of guided-wave propagation characteristics of complex periodic structures. By transforming electromagnetic field variables into a new set of periodic variables, which can also be resolved from the Maxwell's equations, one can convert a periodic guided-wave problem into an equivalent resonator problem. Thus, the FDTD method used for a resonant cavity problem can be adopted to simulate periodic guided-wave structures. In addition, the proposed FDTD algorithm can be extended to model lossy periodic propagation problems. In this study, the substrate integrated nonradiative dielectric waveguide, which is a special type of periodic guided-wave structure subject to a potential leakage loss due to its periodic gaps, is investigated as a showcase. The proposed method is first validated and is then used to analyze the guided-wave characteristics of substrate integrated nonradiative dielectric waveguides. It is shown that the substrate integrated nonradiative dielectric waveguide structure, which can easily be fabricated in planar form, has a well-behaved propagation property suitable for high-performance millimeter-wave circuit design. View full abstract»

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  • Design of Synthetic Quasi-TEM Transmission Line for CMOS Compact Integrated Circuit

    Page(s): 2512 - 2520
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2166 KB) |  | HTML iconHTML  

    This paper presents the design guidelines of the synthetic quasi-TEM transmission line (TL) based on standard 0.18 mum one-poly six-metal complementary metal-oxide-semiconductor (CMOS) technology. The synthetic quasi-TEM TL, also called the complementary-conducting-strip transmission line (CCS TL), is composed of five structural parameters to synthesize its guiding characteristics. Twenty-four designs of CCS TL are reported, with the following unique attributes. First, a characteristic impedance range of 8.62-104.0 Omega is yielded. Second, the maximum value of the slow-wave factor is 4.79, representing an increase of 139.5% over the theoretical limit of the quasi-TEM TL. Third, the ratio of the area of the CCS TL to its corresponding quality factor ( factor) can help to estimate the cost of the loss for the circuit miniaturizations. Additionally, the important CMOS manufacturing of metal density is for the first time involved in the reported TL designs. By following the proposed design methodologies, a practical design example of a -band CMOS rat-race hybrid is reported and experimentally examined in detail to reveal the feasibility of the proposed design guidelines to synthesize the CMOS CCS TL. The chip size without contact pads is 420.0 mum 540.0 mum. The measured loss and isolation of the hybrid at 36.3 GHz are 3.84 and 58.0 dB, respectively. View full abstract»

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  • Analysis and Design of Monolithic Rectangular Coaxial Lines for Minimum Coupling

    Page(s): 2521 - 2530
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1507 KB) |  | HTML iconHTML  

    Coupling through holes etched in a common wall between the neighboring surface micromachined rectangular coaxial lines is studied in this paper. Analytical models for single- and multiple-hole structures are developed using Bethe's small aperture theory, and excellent agreement with finite-element and finite-integration simulations is obtained. These models are used in a circuit-level simulator for efficient optimization of the selected multihole structure. An isolation test structure composed of 200-m center-to-center separated 300-m-tall 50-W rectangular coaxial lines is designed, built, and measured. Coupling levels below 55 dB over 1-cm-long coupling lengths are achieved throughout the -band. It is found that the probe radiation is more than 10 dB higher than the coupling through the common wall holes. This radiation severely affects the accuracy of the measurements and has to be considered when the coupling through the common walls is analyzed. View full abstract»

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  • Calculation of the Properties of Reentrant Cylindrical Cavity Resonators

    Page(s): 2531 - 2538
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB) |  | HTML iconHTML  

    The lowest resonant frequencies of reentrant cylindrical cavity resonators are calculated using the method of moments to obtain upper and lower bounds. The accuracy and convergence of the results are investigated and the factors and shunt impedances calculated. A simple empirical assumption about the choice of basis functions leads to results that are of good accuracy and readily computed. The results obtained are compared with those of experiment and from calculations using MAFIA and Microwave Studio. View full abstract»

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  • A Space-Mapping Approach to Microwave Device Modeling Exploiting Fuzzy Systems

    Page(s): 2539 - 2547
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (701 KB) |  | HTML iconHTML  

    We present a novel surrogate modeling methodology based on a combination of space mapping and fuzzy systems. Fine model data, the so-called base set, is assumed available in the region of interest. Although we do not assume any particular location of the base points, it is preferable that they form a uniform mesh. The standard space-mapping surrogate is established using available fine model data. The fuzzy system is then set up to interpolate the differences between the space-mapping surrogate and the fine model at all base points. Our new methodology offers significant advantages with respect to some of the previous space-mapping approaches to modeling, which are: (1) it handles any base set and (2) the number of space-mapping parameters does not limit the accuracy of the surrogate. Moreover, it exhibits comparable or better accuracy than the recently published modeling technique utilizing space mapping and radial basis functions. We also consider a hierarchical fuzzy space-mapping modeling, which relies on a fuzzy interpolation of space-mapping parameters and subsequent fuzzy interpolation of the residuals between the fine and surrogate model. Examples demonstrate the robustness of our approach and give a comparison with other space-mapping-based modeling techniques. View full abstract»

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  • Synthesis of Compact Lumped Models From Electromagnetic Analysis Results

    Page(s): 2548 - 2554
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    Synthesis of compact lumped (RLC) models from the results of an electromagnetic (EM) analysis of planar circuits is described. The technique requires precise EM analysis S-parameter data at two or more frequencies. Data at up to five frequencies allows synthesis of more complicated models. For each port-to-port (i.e., ldquobranchrdquo) connection, 662 potential branch models are first synthesized and tested. Branch models that best match the EM results at all nonsynthesis frequencies are selected. For structures for which a compact lumped model is appropriate, this technique yields models that often provide direct physical insight into the electrical nature of the modeled structure. For electrically large structures, the technique is extended by the use of supplemental internal EM analysis ports. The technique is closed form; iteration is not used. View full abstract»

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  • Design of a High-Power Superconducting Filter Using Resonators With Different Linewidths

    Page(s): 2555 - 2561
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB) |  | HTML iconHTML  

    This paper presents a design method to develop a high-power superconducting microstrip filter with different linewidth resonators. The linewidth of every resonator is optimized using this method to meet the same maximum current density. Thus, the power-handling capability of the five-pole filter on a limited substrate size can reach a maximum value. The design method is verified by the electromagnetic simulation of the current density distribution. The high-power superconducting filter is designed and fabricated on a 38 mm times 30 mm times 0.505 mm LaAlO3 substrate. The maximum resonator linewidth is 7 mm, and the minimum one is 1.6 mm. The filter has a center frequency of 2006 MHz and a narrow bandwidth of 1.0%. The measured power level is up to 35 dBm at 65 K without an evident change in insertion loss. View full abstract»

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  • Input and Output Cross-Coupled Wideband Bandpass Filter

    Page(s): 2562 - 2568
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (691 KB) |  | HTML iconHTML  

    A new wideband bandpass filter configuration with input-output cross-coupling is investigated. The new filter is based on a transmission line filter with short-circuited stubs. In order to allow the filter to exhibit high selectivity filtering characteristic and to enhance the group delay with only a few resonators, cross-coupling between the input and output feed lines is introduced. As a result, new symmetrical pairs of transmission zeros are generated at the lower and upper stopbands, leading to a quasi-elliptic function response that improves the passband and out-of-band performances. A general circuit model for the proposed filter is presented and a demonstrator with approximately 48% ripple bandwidth at a midband frequency of 3 GHz is developed. The design is successfully realized in theory and verified by full-wave electromagnetic simulation and the experiment, where excellent agreement is obtained. View full abstract»

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

    Page(s): 2569 - 2578
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (925 KB) |  | HTML iconHTML  

    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. View full abstract»

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  • A Physical Model of Solenoid Inductors on Silicon Substrates

    Page(s): 2579 - 2585
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (671 KB) |  | HTML iconHTML  

    In this paper, a physical model is presented to predict the frequency-dependent characteristics of solenoid-type inductors on standard silicon substrates. The model considers the skin-depth effect in the conductor, interwinding capacitance, parasitic capacitance between the conductor and substrate, substrate resistance, and substrate capacitance of a solenoid inductor on the silicon substrate, which are all computed based on the inductor's geometric dimensions and related material properties. Surface-micromachined inductors of various geometries have been tested to validate the physical model and found a satisfactory consistency between the measured results and the theoretical predictions in the multigigahertz frequency range. It is also suggested that the increase of the solenoid aspect ratio is beneficial in enhancing quality factors of solenoid inductors on the silicon substrate at a high frequency. View full abstract»

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  • Half Mode Substrate Integrated Waveguide 180° 3-dB Directional Couplers

    Page(s): 2586 - 2592
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1678 KB) |  | HTML iconHTML  

    In this paper, two types of half mode substrate integrated waveguide 180deg couplers are proposed, the phase-shifting structures of which are composed of metallic via fins or etched air slots. Each coupler maintains the good performance of the substrate integrated waveguide coupler with a half reduction in size and a 180deg phase difference between through and coupling ports. Prototypes working in the C-,X -, Ku-, and Ka-bands are designed and fabricated using the standard printed circuit board process. The consistency between the measured data and simulated results shows that the proposed couplers have the merits of low profile and good performance. View full abstract»

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  • Reduced-Length Rat-Race Couplers

    Page(s): 2593 - 2598
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1015 KB) |  | HTML iconHTML  

    In this paper, analysis of a rat-race coupler having three equal arms of arbitrary electrical length is presented. All of these couplers have lower characteristic impedances than the conventional 1.5-lambda coupler and some of them have smaller electrical lengths. Bandwidths in terms of isolation, matching, amplitude, and phase imbalances are also discussed. A reduced-size rat-race coupler of length 19lambda/18 at the operating frequency of 0.9 GHz has been fabricated in the microstrip line. Experimental results agree well with the theoretical predictions. View full abstract»

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  • Time-Varying Matching Networks for Signal-Centric Systems

    Page(s): 2599 - 2613
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1819 KB) |  | HTML iconHTML  

    A time-varying matching network is proposed for signal-centric systems. This matching network achieves significantly higher bandwidth than conventional designs with the same circuit topology and complexity. This is achieved by exploiting information about the incident pulse. Time-varying elements control the initial conditions of the reactive components so that excellent matching is obtained over a very wide frequency range. In particular, experimental and theoretical results show that a single-stage LC ladder with one single-pole double-through switch achieves a nearly perfect match with negligible dispersion for a monocycle with a 10:1 10-dB bandwidth. Unlike conventional matching networks, time-varying designs are not limited by Bode-Fano gain-bandwidth restrictions, but only by the nonidealities of their circuit components. Moreover, it is experimentally shown that tunable time-varying designs reduce the reflected energy by 40%-45% and improve the transmitted energy efficiency of the same monocycles by 20%-25% compared to conventional tunable designs of the same complexity. View full abstract»

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  • Multigigahertz Causal Transmission Line Modeling Methodology Using a 3-D Hemispherical Surface Roughness Approach

    Page(s): 2614 - 2624
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1119 KB) |  | HTML iconHTML  

    As computer clock speeds continue to increase at a rate dictated by Moore's Law, the system buses must also scale in proportion to the processor speed. As data rates increase beyond ~5 Gb/s, the historical methods used to model transmission lines start to break down and become inadequate for the proper prediction of signal integrity. Specifically, the traditional approximations made in transmission line models, while perfectly adequate for slower speeds, do not properly account for the extra losses caused by surface roughness and do not model the frequency dependence of the complex dielectric constant, producing incorrect loss and phase-delay responses, as well as noncausal waveforms in the time domain. This paper will discuss the problems associated with modeling transmission lines at high frequencies, and will provide a practical modeling methodology that accurately predicts responses for very high data rates. View full abstract»

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  • A Novel 180° Hybrid Using Broadside-Coupled Asymmetric Coplanar Striplines

    Page(s): 2625 - 2630
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (792 KB) |  | HTML iconHTML  

    In this paper, a new way to realize a 180deg hybrid is presented. This technique utilizes a broadside-coupled asymmetric coplanar-stripline section to meet the tight coupling requirement that usually arises from the traditional reduced-size hybrid-ring configuration. In addition, this coplanar technique facilitates the implementation of a hybrid ring in a cascadable format. While providing a simple design procedure for the device, analytical details are also discussed. An experimental prototype, operating at 2.4 GHz, has been fabricated using conventional printed circuit board technology. Measured performances show good agreement with analytical and full-wave simulations, showing promising potential for a variety of applications such as balanced mixers, power amplifiers, and antenna feed networks. View full abstract»

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  • Frozen Modes in Parallel-Plate Waveguides Loaded With Magnetic Photonic Crystals

    Page(s): 2631 - 2641
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (777 KB) |  | HTML iconHTML  

    We examine parallel-plate magnetic photonic crystal (MPC) waveguides comprised of a periodic loading with two anisotropic layers and one ferrite layer on each period. It is shown that, at a specific design frequency , parallel-plate MPC waveguides can support a Bloch mode with zero axial group velocity similar to the ldquofrozen moderdquo regime of the prototypical 1D MPC structure. When the proposed 2D structure is illuminated with a properly polarized time-harmonic wave, near unity power transmission (coupling) into the frozen mode occurs, and field strength within the MPC becomes orders of magnitude larger than the incident field strength. The steady-state case is evaluated using both analytical tools and finite elements, while the finite-difference time-domain method is applied to evaluate the 2D MPC transient response. View full abstract»

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  • Surface Micromachined Microelectromechancial Ohmic Series Switch Using Thin-Film Piezoelectric Actuators

    Page(s): 2642 - 2654
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1941 KB) |  | HTML iconHTML  

    This paper presents results on a surface micromachined RF microelectromechanical switch that uses piezoelectric actuators. The switch uses solution chemistry-derived lead zirconate titanate thin films spun deposited onto a high-resistivity silicon substrate with coplanar waveguide transmission lines. Actuation voltages, applied via circuits independent of the RF circuitry, average less than 10 V, with switch operation demonstrated as low as 2 V. The series switch exhibits better than 20-dB isolation from dc up to 65 GHz and as large as 70 dB below 1 GHz. In the closed state, the switch has an insertion loss less than 1 dB up to 40 GHz, limited in this demonstration by substrate losses from the elastic layer used to stress control the piezoelectric actuators. Switching speeds for the different designs are in the range of 40-60 ms. Thermal sensitivity measurements show no change in isolation observed for temperatures up to 125degC. However, an increase in actuation voltage is required at elevated temperatures. View full abstract»

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  • IEEE Transactions on Microwave Theory and Techniques information for authors

    Page(s): 2655
    Save to Project icon | Request Permissions | PDF file iconPDF (21 KB)  
    Freely Available from IEEE
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    Page(s): 2656
    Save to Project icon | Request Permissions | PDF file iconPDF (318 KB)  
    Freely Available from IEEE

Aims & Scope

The IEEE Transactions on Microwave Theory and Techniques focuses on that part of engineering and theory associated with microwave/millimeter-wave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities. Microwave theory and techniques relates to electromagnetic waves usually in the frequency region between a few MHz and a THz; other spectral regions and wave types are included within the scope of the Society whenever basic microwave theory and techniques can yield useful results. Generally, this occurs in the theory of wave propagation in structures with dimensions comparable to a wavelength, and in the related techniques for analysis and design..

Full Aims & Scope

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Dominique.Schreurs@ieee.org

Editor-in-Chief
Jenshan Lin
jenshan@ieee.org