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Microwave Theory and Techniques, IEEE Transactions on

Issue 7 • Date July 2012

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Displaying Results 1 - 25 of 32
  • Table of contents

    Publication Year: 2012 , Page(s): C1 - C4
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  • IEEE Transactions on Microwave Theory and Techniques publication information

    Publication Year: 2012 , Page(s): C2
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  • A New High-Efficient Spectral-Domain Analysis of Single and Multiple Coupled Microstrip Lines in Planarly Layered Media

    Publication Year: 2012 , Page(s): 2025 - 2034
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2410 KB) |  | HTML iconHTML  

    The analysis of propagation of bound and leaky modes in single and multiple coupled microstrip lines in planarly layered media by means of Galerkin's method applied to an electric field integral-equation formulation in the spectral domain with Chebyshev polynomials basis functions weighted with the edge behavior of the unknown surface current densities on the metallic strips leads to the evaluation of improper integrals of oscillating functions with a slow asymptotic decay. In this paper, a new analytical technique for drastically speeding up the computation of such integrals is presented. First, suitable half-space contributions are pulled out of the kernels, which makes the integrands exponentially decaying functions. The integrals of the extracted contributions are then expressed as combinations of proper integrals and fast converging improper integrals by means of appropriate integration procedures in the complex plane. View full abstract»

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  • A Generalized Multiple Scattering Method for Dense Vias With Axially Anisotropic Modes in an Arbitrarily Shaped Plate Pair

    Publication Year: 2012 , Page(s): 2035 - 2045
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2675 KB) |  | HTML iconHTML  

    Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the numerical addition theorems and the GMS method have been validated by comparing results with either analytical expressions for special cases or full-wave simulations for more general cases. Several examples are provided to demonstrate the advantages of the generalized method over previous via models by taking into account the axially anisotropic modes due to the asymmetry caused by dense vias and/or arbitrarily shaped power/ground plate edges on via performance. View full abstract»

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  • Modeling of Waveguide Structures Using DG-FETD Method With Higher Order Tetrahedral Elements

    Publication Year: 2012 , Page(s): 2046 - 2054
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1915 KB) |  | HTML iconHTML  

    In this paper, the discontinuous Galerkin (DG) finite-element time-domain (FETD) method is developed to model electromagnetic (EM) structures with waveguide excitations. Several specific issues about the DG-FETD modeling are addressed. First, the higher order tetrahedral elements are employed to accurately model the geometry of EM structures and effectively reduce the dispersion error so that the efficiency of the FETD method is increased. To further increase the efficiency of the DG-FETD method, the local time-stepping scheme is applied. Secondly, the conformal perfect matching layer (PML) is applied to terminate the waveguide. The formulation of the conformal PML is presented in this paper. Thirdly, a novel approach is proposed to extract the S-parameters of waveguide structures. This approach applies the surface magnetic current to excite the EM fields in the waveguide structures. Taking advantage of the relationship between the excitation current and excited fields in the uniform waveguide, one can readily obtain the incident electric fields that are required for calculating the S-parameters. This approach avoids the pre-simulation of the uniform waveguide. Finally, the numerical results are given to validate the DG-FETD modeling. View full abstract»

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  • A Comprehensive Analysis of the Absorption Spectrum of Conducting Ferromagnetic Wires

    Publication Year: 2012 , Page(s): 2055 - 2065
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2565 KB) |  | HTML iconHTML  

    A detailed analysis of the absorption spectrum of conductive ferromagnetic wires is presented. The absorption spectrum is computed from the solution to the scattering problem, and circuit models are formulated to clarify the interplay between losses, skin effect, and wire geometry. Both infinitely long wires and the axial resonances introduced by finite-length wires are considered. The theoretical results are validated experimentally through measurements within a metallic rectangular waveguide. View full abstract»

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  • High-Performance Solenoidal RF Transformers on High-Resistivity Silicon Substrates for 3D Integrated Circuits

    Publication Year: 2012 , Page(s): 2066 - 2072
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2262 KB) |  | HTML iconHTML  

    Soleniod-like transformers based on a traveling-wave design and using advanced through silicon via process technology are reported for operation at frequencies from 1 to 14 GHz. The symmetrical 1:1 transformers are designed as compact slow-wave transmission-line structures with well-defined signal return paths. One-, two-, three-, and four-turn transformers have 1-dB bandwidths ranging from 6 to 9.2 GHz, and midband insertion losses from 0.24 to 0.37 dB. The measured intrinsic loss is 0.46 dB or less up to 10 GHz, and 0.97 dB up to 14 GHz. Relatively simple and scalable physically based lumped-element circuit models accurately predict the performance of these low parasitic transformers. View full abstract»

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  • Complex Impedance Transformers Consisting of Only Transmission-Line Sections

    Publication Year: 2012 , Page(s): 2073 - 2084
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2519 KB) |  | HTML iconHTML  

    Design methods are, for the first time, suggested for the complex impedance transformers, to solve the conventional problem of imaginary value of characteristic impedance of transmission-line sections. The complex impedance transformers consist of only transmission-line sections, and the design formulas are the function of the reίection coefficients of the complex termination impedances. Firstly, the impedance transformers that transform a complex impedance into a real one are discussed. Secondly, those transforming a complex impedance to another complex one are studied. For the impedance transformers of the first type, the regions of the Smith chart where one complex impedance can be transformed into one real one by only one transmission-line section are called allowed regions, while the outside forbidden regions. Depending on where the complex impedances are located, a method to reduce the size is discussed in more detail. For the second case where both termination impedances are complex, the complex conjugate of one of two complex impedances should be located on a Smith chart for maximum power transfer. The design formulas are then obtained in a similar manner. To validate the design formulas, three impedance transformers terminated in a fixed complex impedance of (1000 - j30) Ω and three real impedances of 50, 60, and 80 Ω are fabricated and measured. The measured results show quite good agreement with prediction, return losses of 30-38 dB being achieved around the design center frequency of 2 GHz. View full abstract»

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  • A Rigorous Design Methodology for Compact Planar Branch-Line and Rat-Race Couplers With Asymmetrical T-Structures

    Publication Year: 2012 , Page(s): 2085 - 2092
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2204 KB) |  | HTML iconHTML  

    In this paper, a rigorous design methodology is developed to design compact planar branch-line and rat-race couplers using asymmetrical T-structures. The quarter-wave transmission line, namely the basic element for realizing the coupler, can be replaced by the asymmetrical T-structure, which is composed of a low-impedance shunt stub and two series high-impedance lines with unequal electrical lengths. As compared with the use of the conventional symmetrical T-structure, employing the asymmetrical one to implement the coupler not only has the advantage of flexibly interleaving the shunt stubs to achieve a more compact circuit size, but also provides a wider return loss bandwidth. Based on the proposed designed methodology, the asymmetrical T-structure can be exactly synthesized and then applied to implement the compact planar couplers. The developed planar branch-line coupler occupies 12.2% of the conventional structure and has a 35.5% 10-dB return loss bandwidth. On the other hand, the rat-race coupler is miniaturized to a 5% circuit size and developed with a 29.5% 20-dB return loss bandwidth. View full abstract»

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  • Prediction of Multipactor Breakdown for Multicarrier Applications: The Quasi-Stationary Method

    Publication Year: 2012 , Page(s): 2093 - 2105
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2456 KB) |  | HTML iconHTML  

    A new prediction algorithm for multipactor breakdown determination in multicarrier signals is presented. This new algorithm assumes a quasi-stationary (QS) model based on the nonstationary theory for single-carrier signals. It determines the worst case, i.e., the combination of signal phases that yields the lowest breakdown level per carrier, using multipactor electron growth models. It considers the secondary emission yield properties of the material and the time-varying value of the multicarrier signal envelope. View full abstract»

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  • Application of Stepped-Impedance Technique for Bandwidth Control of Dual-Band Filters

    Publication Year: 2012 , Page(s): 2106 - 2114
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2004 KB) |  | HTML iconHTML  

    This paper demonstrates application of the popular stepped-impedance technique to control the bandwidths of dual-band filters independently. Unlike previous dual-band stepped-impedance filters, the role of the stepped-impedance technique is to control the bandwidths of the two bands rather than to provide dual-band performance. The exact relationship between stepped-impedance ratios and the ratio of the two absolute bandwidths is obtained through rigorous analysis. Moreover, since the proposed filters can be synthesized with popular transmission lines and coupled lines that are very-well characterized, time-consuming full-wave simulation can be minimized. Along with the complete set of design equations, experimental results for transmission-line and coupled-line dual-band filters are provided that verify the proposed approach. View full abstract»

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  • Harmonic Suppressed Dual-Band Bandpass Filters With Tunable Passbands

    Publication Year: 2012 , Page(s): 2115 - 2123
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1836 KB) |  | HTML iconHTML  

    This paper presents a novel approach to the design of tunable dual-band bandpass filter with broadband harmonic suppression characteristics. The proposed filter structure offers the possibility of two tunable passbands, as well as a fixed first passband and controllable second passband. The tunable passband frequency usually causes a shift of the harmonics, which need to be suppressed to improve out-of the passband characteristics. In order to suppress the harmonics over a broad bandwidth, defected ground structures are used at input and output feeding lines without degrading the passbands characteristics. Both theory and experiment are provided to validate the proposed filter. From the experimental results, it is found that the proposed filter exhibits a first passband center frequency tunable range of 34.14% from 0.85 to 1.2 GHz with the almost constant 3-dB fractional bandwidth (FBW) of 13% and second passband center frequency tunable range of 41.81% from 1.40 to 2.14 GHz with the 3-dB FBW of 11%. The measured results of the proposed filters show a rejection level of 20 dB up to more than ten times of second passband frequency can be obtained, thereby ensuring broad harmonics rejection characteristics without degradation of passbands. The measurement data have good agreement with the simulation. View full abstract»

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  • Design of High-Order Wideband Planar Balun Filter in S -Plane Bandpass Prototype

    Publication Year: 2012 , Page(s): 2124 - 2130
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1429 KB) |  | HTML iconHTML  

    A new high-order wideband planar balun filter is proposed in this paper. The balun filter is exact synthesized based on S-domain bandpass prototype using Richards' Theorem to fit the user-defined specifications. By analyzing the redundant element in the equivalent circuit, the output impedance of the balun filter can be arbitrarily assigned. To use an S-plane bandpass prototype other than a high-pass prototype can shrink the circuit area and improve the stopband performance. The lumped capacitor approximation suppresses the spurious response in the stopband and further reduces the circuit size. A high-order balun filter with a bandwidth of 100% and a reflection coefficient of -15 dB is implemented by combining of microstrip lines, slotlines, and coplanar striplines. The simulation and measurement results match well. View full abstract»

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  • On the Relation Between Stored Energy and Fabrication Tolerances in Microwave Filters

    Publication Year: 2012 , Page(s): 2131 - 2141
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2757 KB) |  | HTML iconHTML  

    In this paper, a new approach for the sensitivity analysis of microwave filter networks is presented. It is shown that the standard method of sensitivity calculation based on a tuned filter is only valid for infinitesimal geometry changes and not meaningful for practical tolerance values. However, when the sensitivity calculation is expanded to also include sensitivities of detuned filters, it is shown that accurate tolerance predictions can be made even for large geometry variations. It is found that sensitivities can be related to the stored energy distribution in the filter. Transversal and ladder network-type topologies are examined, and it is demonstrated for the first time that, for in-line topologies, sensitivity can be predicted directly from the group delay of the filter in Chebyshev filters. In order to demonstrate the usefulness of the results obtained, the maximum degradation of the in-band performance has been directly obtained from the group delay for different inline filters. View full abstract»

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  • A Novel Compact Printable Dual-Polarized Chipless RFID System

    Publication Year: 2012 , Page(s): 2142 - 2151
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2563 KB) |  | HTML iconHTML  

    A novel compact design of an ultralow-cost fully printable slot-loaded dual-polarized chipless radio frequency identication tag is presented with four near- and far-field reading techniques. The tag consists of four rectangular metallic patches loaded with multiple slot resonators. Slots with the same polarization for adjacent frequencies are placed alternately into two patches to reduce the mutual coupling between the slots. Then two similar sets are placed in horizontal and vertical polarizations to double the number of bits within the same frequency bandwidth. The tag can be detected using dual-polarized waveguide(s) or dual-polarized antennas. This single-sided compact chipless tag has higher data capacity and lower cost compared with the existing printable chipless tags and can be used in personal ID or credit cards and banknotes and can be directly printed on paper or plastic packets for item-level tagging. View full abstract»

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  • Self-Biased Nonreciprocal Microstrip Phase Shifter on Magnetic Nanowired Substrate Suitable for Gyrator Applications

    Publication Year: 2012 , Page(s): 2152 - 2157
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1268 KB) |  | HTML iconHTML  

    Magnetic nanowired substrates (MNWS) have been used for the fabrication of a planar nonreciprocal microstrip device. It shows a differential phase shift of 300 degrees cm-1 at K a -band without requiring the application of a dc bias magnetic field, and making it suitable for miniaturized gyrator applications. The nonreciprocal operation is achieved by loading the device with nanowires of different ferromagnetic materials. This allows to control the phase velocity of the microwave signal passing through the device by virtue of the spatial variation of the MNWS permeability. The measured microwave performances of the device have been reproduced with excellent accuracy using a proposed analytical model based on an effective medium theory and useful for the prediction of further tunable capabilities. View full abstract»

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  • Microwave and RF p-i-n Diode Model for Time-Domain Simulation

    Publication Year: 2012 , Page(s): 2158 - 2164
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1194 KB) |  | HTML iconHTML  

    A dynamic time-domain model suitable for simulating the behavior of high-speed high-power p-i-n diodes is presented. This time-domain model accurately describes not only the charge storage behavior in the p-i-n diode in forward bias, but also the reverse-bias capacitance and resistance as a function of reverse voltage. A SPICE implementation of the time-domain model is fully described and a spreadsheet is being made available to the microwave community. The time-domain model is verified with experimental data and good agreement was obtained in both diode bias states. Three applications describing the linear, nonlinear, and transient behavior of the p-i-n diode simulated using the time-domain model are also presented. This improved time-domain model and associated SPICE implementation allows full modeling of high-speed high-frequency p-i-n diodes. View full abstract»

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  • A Dual-Resonant Mode 10/22-GHz VCO With a Novel Inductive Switching Approach

    Publication Year: 2012 , Page(s): 2165 - 2177
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3209 KB) |  | HTML iconHTML  

    This paper presents a novel dual-band voltage-controlled oscillator (VCO) in a standard 0.18-μm CMOS technology. With special design in the LC tank, the circuit exhibits two oscillation modes in different frequency bands. The frequency band selection is achieved by a switched coupled inductor with the tunable inductance and quality factor. This VCO can operate in a 10-GHz band with 7.6% tuning range and a 22-GHz band with 8% tuning range, while the core circuit draws a dc current of 8.44 mA from a 1.8-V supply voltage. The figures-of-merit at 10- and 22-GHz bands are - 184.63 and - 181.81 dBc/Hz, respectively. These performances are comparable with state-of-the-art dual-band LC-VCOs. View full abstract»

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  • Design and Analysis of an Ultra-Wideband Automatic Self-Calibrating Upconverter in 65-nm CMOS

    Publication Year: 2012 , Page(s): 2178 - 2191
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4322 KB) |  | HTML iconHTML  

    In this paper, an ultra-wideband (UWB) upconverter is proposed that has automatic self-calibrating circuits for the in-phase/quadrature mismatch correction and the local (LO) leakage suppression. The proposed self-calibrating circuits have been devised to have UWB functionality without help of the baseband processor. In addition, calibrating circuits do not need any additional analog-to-digital converter or sample-and-hold capacitors that are used to store and update the minimum power because the proposed calibrators find the solution from informations in current state. To verify the performance, the upconverter was applied to an UWB transmitter (Tx), operating from 3.1 to 4.8 GHz and from 6.3 to 9 GHz in 65-nm CMOS. The measured data shows UWB performance for the sideband rejection up to 9 GHz and the LO leakage suppression up to 5 GHz, respectively. The automatically calibrated Tx has error vector magnitude of lower than -20 dB, output 1-dB compression point of -6 dBm, LO leakage of lower than -43 dBm, and sideband suppression ratio of higher than 45 dBc with current consumption of 175 mA from a 1.2-V power supply for all supporting bands and time frequency codes defined in WiMedia UWB specifications. View full abstract»

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  • A Fully Integrated 0.18- \mu{\hbox {m}} CMOS Transceiver Chip for X -Band Phased-Array Systems

    Publication Year: 2012 , Page(s): 2192 - 2202
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2231 KB) |  | HTML iconHTML  

    An X-band core chip is designed and fabricated in 0.18- CMOS technology, which can significantly reduce the monolithic microwave integrated circuit count required for realizing an active beam-former T/R module. The core chip consists of two RX/TX paths, each of which includes a 6-b phase shifter, a 6-b attenuator, along with two input and output amplifiers. A new architecture for realizing such a core chip system and a low loss circuit for 5.625° phase shift block are proposed. The overall rms phase and gain errors are better than 2° and 0.25 dB, respectively, in both RX/TX paths. The gain of each path is around 12 dB, while the output 1-dB compression point is higher than 10 dBm over the band of interest. View full abstract»

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  • Device Characterization Techniques Based on Causal Relationships

    Publication Year: 2012 , Page(s): 2203 - 2219
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4359 KB) |  | HTML iconHTML  

    In this paper, we introduce a novel technique for vector network analyzer (VNA) scattering parameter (S -parameter) device characterization. The presented approach is based on causal relationships that provide a connection between the real and imaginary parts as well as between the magnitude and phase of causal network functions. We discuss the problems encountered in the practical implementation of the dispersion relationships such as numerical evaluation of the singular integrals, finite bandwidth of the experimental data, reconstruction artifacts, and nonuniqueness of dispersion relationships. To reduce these problems, we use the generalized dispersion relationships with reference points (subtractions). We develop integral relationships with subtractions and corresponding estimates for error bounds. We show that an appropriate placement of the reference points can significantly reduce the errors caused by finite spectrum. We analyze the applicability of the developed dispersion relationships to the VNA measurements. We demonstrate that certain parameters can be measured with considerably higher accuracy compared with other parameters and that it is possible to select samples from the measured data that can be used as reference points for dispersive integrals. Based on these observations, we propose a device characterization technique that consists of the causality-constrained reconstruction of the sensitive parameters of the measured devices based on more accurately measured characteristics. The proposed technique allows one to accurately characterize the parameters, like quality factor of a high-quality (high- Q) inductors or loss tangent of low-loss transmission lines, of which direct measurement is normally not possible due to limited sensitivity and dynamic range of the VNA. To demonstrate the effectiveness of the proposed technique, we reconstruct the resistance and the quality factor of a high-Q inductor from the accurately measured inductance. View full abstract»

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  • Multimode TRL Calibration Technique for Characterization of Differential Devices

    Publication Year: 2012 , Page(s): 2220 - 2247
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4934 KB) |  | HTML iconHTML  

    In this paper, a new comprehensive analytical derivation and discussion of the multimode thru-relfect-line (TRL) calibration based on the new generalized reverse cascade matrices is presented. The advantage of the presented formulation is that it can account for certain symmetries in the measurement setup and reflect them in the symmetry of the derived relationships. The focus is on the two-mode case since this covers the majority of the practical applications. To demonstrate the effectiveness of the new formulation, the practical use of the multimode TRL calibration technique for de-embedding purposes is discussed. The common de-embedding assumptions such as reciprocity and symmetry are analyzed and their consequences on the multimode TRL calibration are discussed. It is shown that these assumptions applied to the embedding networks can reduce the requirements on the reflect standard. The use of the multimode TRL calibration technique for un-terminating purposes is discussed. It is demonstrated that in the special de-embedding case it is possible to completely characterize the partially leaky embedding networks. The problems of interpretation and re-normalization of the measured scattering parameters are also discussed. Finally, the on-wafer measurement results are presented that verify the multimode TRL approach for four-port vector network analyzer calibration and de-embedding of differential devices. View full abstract»

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  • Simple Test and Modeling of RFID Tag Backscatter

    Publication Year: 2012 , Page(s): 2248 - 2258
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2432 KB) |  | HTML iconHTML  

    We consider here worst-case analysis of backscatter from passive radio frequency identification (RFID) tags. The basis is a figure of merit “B” to relate link power at reader ports to tag circuit parameters. A minimum bound for received monostatic backscatter can be determined by inspection from measured B. The bound is general for narrowband signals in any causal linear propagation. For an assembled tag, this minimum varies only with reader transmit power, tag antenna tuning, and chip power sensitivity of different commands. To validate this model, we propose a backscatter calibration device to enable measurements with estimated 0.5 dB uncertainty. We then demonstrate how the minimum bound can inform reader sensitivity specification to help ensure reliable inventory performance. View full abstract»

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  • Broadband Tissue-Equivalent Phantom for BAN Applications at Millimeter Waves

    Publication Year: 2012 , Page(s): 2259 - 2266
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1234 KB) |  | HTML iconHTML  

    The extension of body area networks from microwaves to millimeter waves requires to develop experimental phantoms emulating the dielectric properties of human skin for the accurate, reproducible, and well-controlled characterization of wearable antennas, on-body propagation channel, and absorption of the electromagnetic power by the human body. Here we introduce a broadband skin-equivalent semisolid phantom whose composition is optimized to coincide with measured values of the human skin permittivity in the 55-65-GHz range. To confirm the accuracy of this phantom, specific absorption rate measurements are performed at 60 GHz using a temperature-based approach. An excellent agreement between the experimental and numerical results is demonstrated. View full abstract»

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  • Mechanisms of RF Electromagnetic Field Absorption in Human Hands and Fingers

    Publication Year: 2012 , Page(s): 2267 - 2276
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3904 KB) |  | HTML iconHTML  

    The absorption of electromagnetic fields in the hand is investigated over the 900-3700-MHz frequency range. This enables the determination of the envelope of the peak spatial specific absorption rate in the hand. It also provides a basis for deriving measurement procedures for evaluating compliance of wireless devices with specific absorption rate limits in the hands. Both plane waves and dipole antennas are used to investigate the patterns of RF absorption in hand and finger tissue models for far- and near-field exposures. The results demonstrate that absorption enhancements are found in the hand that are not present in a standardized flat phantom. Enhancements of several decibels are observed, depending on the model parameters. A method to conservatively estimate the exposure in the hand based on flat phantom measurements is proposed. View full abstract»

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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..

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