Scheduled System Maintenance:
On May 6th, single article purchases and IEEE account management will be unavailable from 8:00 AM - 5:00 PM ET (12:00 - 21:00 UTC). We apologize for the inconvenience.
By Topic

Microwave Theory and Techniques, IEEE Transactions on

Issue 12  Part 2 • Date Dec. 2011

 This issue contains several parts.Go to:  Part 1 

Filter Results

Displaying Results 1 - 25 of 41
  • [Front cover]

    Publication Year: 2011 , Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (1703 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Microwave Theory and Techniques publication information

    Publication Year: 2011 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (45 KB)  
    Freely Available from IEEE
  • Table of contents

    Publication Year: 2011 , Page(s): 3261 - 3262
    Save to Project icon | Request Permissions | PDF file iconPDF (50 KB)  
    Freely Available from IEEE
  • Editorial

    Publication Year: 2011 , Page(s): 3263
    Save to Project icon | Request Permissions | PDF file iconPDF (20 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • FDTD/GSM Analysis of Multilayered Periodic Structures With Arbitrary Skewed Grid

    Publication Year: 2011 , Page(s): 3264 - 3271
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB) |  | HTML iconHTML  

    An efficient algorithm to compute the scattering properties of a multilayered periodic structure with an arbitrary skewed grid using a hybrid finite-difference time-domain/generalized scattering matrix technique is described. In this algorithm, the constant horizontal wavenumber approach for an arbitrary skewed grid is used to compute the scattering parameters of each periodic layer. A complete Floquet harmonic analysis of the periodic structure is presented, where propagation and evanescent behaviors of Floquet harmonics are studied. In addition, guidelines for higher order harmonics selection for certain layers separation is provided. The validity of this algorithm is verified through the good agreement of the numerical results with those obtained from time- and frequency-domain simulations for the entire structure. Furthermore, accurate results for well-known configurations such as frequency selective surfaces with an arbitrary skewed grid under different angles of incidence are obtained. This algorithm yields accurate results with less computational time and memory usage. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transmission-Line Metamaterials on a Skewed Lattice for Transformation Electromagnetics

    Publication Year: 2011 , Page(s): 3272 - 3282
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (913 KB) |  | HTML iconHTML  

    We propose a lattice of skewed transmission lines to implement a full effective material tensor. First we show, using transformation electromagnetics, how a skewed lattice will introduce off-diagonal components in the material tensor. We then show how this can be extended to a transmission-line network placed on a skewed lattice, using periodic analysis of a 2-D transmission-line network. We also show how to design a 2-D transmission-line unit cell to implement a full-material tensor for 2-D propagation. We confirm our results using full-wave simulation of a unit cell, as well as full-wave simulation of refraction in a transmission-line network between an isotropic effective medium and a anisotropic effective medium. Finally, we show how this idea can be extended to 3-D unit cells for transformation electromagnetics applications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling Material Interfaces and Boundary Conditions in High-Order Finite-Difference Methods

    Publication Year: 2011 , Page(s): 3283 - 3293
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1021 KB) |  | HTML iconHTML  

    When solving the transmission-line equations using high-order finite-difference methods, it is extremely important to have appropriate procedures to enforce boundary conditions as well as the continuity of the fields at material interfaces where the material parameters are discontinuous. This paper presents general procedures to accomplish these two tasks on both uniform and nonuniform grids. The proposed procedures can be used to achieve high-order convergence on coarse grids even in the extreme case of analyzing a dispersive Lorentz material interfaced with vacuum and excited at the plasma frequency of the Lorentz material. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Rigorous Solution to the Low-Frequency Breakdown in Full-Wave Finite-Element-Based Analysis of General Problems Involving Inhomogeneous Lossless/Lossy Dielectrics and Nonideal Conductors

    Publication Year: 2011 , Page(s): 3294 - 3306
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (828 KB) |  | HTML iconHTML  

    Existing methods for solving the low-frequency breakdown problem associated with full-wave solvers rely on low-frequency approximations, which has left a number of research questions to be answered. The conductors are also generally treated as perfect conductors and the dielectric loss is not considered. In this work, a rigorous method that does not utilize low-frequency approximations is developed to eliminate the low frequency breakdown problem for the full-wave finite-element based analysis of general 3-D problems involving inhomogeneous lossless and/or lossy dielectrics and nonideal conductors. This method has been validated by the analysis of realistic on-chip circuits at frequencies as low as dc. Furthermore, it is applicable to both low and high frequencies. In this method, the frequency dependence of the solution to Maxwell's equations is explicitly and rigorously derived from dc to high frequencies. In addition to eliminating the low-frequency breakdown, such a theoretical model of the frequency dependence can be used to understand how the field solution, in a complicated 3-D problem with both lossless/lossy inhomogeneous dielectrics and nonideal conductors, should scale with frequency and at which frequency full-wave effects become important. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Realization of Practical Lumped Element All-Pass Networks for Delay Equalization of RF and Microwave Filters

    Publication Year: 2011 , Page(s): 3307 - 3311
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    All-pass networks of the second order used for delay equalization are described in various textbooks, but are frequently quite unrealizable due to impractical circuit element values. This problem has now been solved using new network transformations having simple design equations. An example is given of an all-pass network used in the design of a lumped element delay-equalized filter having a passband from 1250 to 1500 MHz. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modified Asymmetric Impedance Transformers (MCCTs and MCVTs) and Their Application to Impedance-Transforming Three-Port 3-dB Power Dividers

    Publication Year: 2011 , Page(s): 3312 - 3321
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1402 KB) |  | HTML iconHTML  

    For size reduction and design flexibility of impedance transformers, two modified asymmetric impedance transformers are suggested. They each consist of one open stub and two different transmission-line sections and are named a modified constant conductance-type transmission-line impedance transformer (MCCT) and a modified constant voltage-standing-wave-ratio (VSWR)-type transmission-line impedance transformer (MCVT), depending on where the open stub is located. As their applications, impedance-transforming MCCT- and MCVT-three-port 3-dB power dividers (MCCT- and MCVT-PDs) are presented, and it is found that the isolation circuits should be composed of not only resistance but also capacitance. For high-power applications, MCCT and MCVT Gysel-type PDs are also suggested, and four isolation circuits are developed systematically based on the isolation impedances of the MCCT- and MCVT-PDs. The isolation circuits of the Gysel-type PDs are comprised of three transmission-line sections, shunt resistances connected to ground, and series capacitances/shunt inductances. One MCCT-PD and one MCVT Gysel-type PD are verified by measurements. The measured results show good agreement with the prediction, giving power divisions of -3.08 dB, return losses better than 23.8 dB, and isolation of 24.07 dB at 1 GHz for the MCCT-PD and power divisions of about -3.42 and -3.5 dB, return losses better than 21 dB, and isolation of 28 dB at 2 GHz for the MCVT Gysel-type PD. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On-Chip Single-to-Balanced Multicoupled Line Bandpass Filters With Good Selectivity

    Publication Year: 2011 , Page(s): 3322 - 3330
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1442 KB) |  | HTML iconHTML  

    In this work, on-chip single-to-balanced bandpass filters with good selectivity are proposed. The functions of bandpass filter and balun are integrated using a simple multicoupled line structure along with capacitive loadings. The use of inductor is avoided such that the proposed single-to-balanced bandpass filters can achieve very compact size when implemented on chip. They can be designed with the desired bandpass response and reference impedances through the proposed equivalent-circuit models and design equations. In addition, by introducing two cross-coupled capacitors, one tunable transmission zero can be achieved in either the lower or upper stopband to improve the selectivity. Specifically, two third-order single-to-balanced bandpass filter designs in commercial pHEMT process on 4-mil GaAs substrate with different transmission zero locations are presented. The circuit size is less than 1.02 mm × 0.86 mm for a center frequency of 5.5 GHz and a bandwidth of about 18.18%. The corresponding electrical size is only 0.054λg×0.045λg at the center frequency. Good selectivity and balanced performance are demonstrated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compact Tunable Phase Shifters on Screen-Printed BST for Balanced Phased Arrays

    Publication Year: 2011 , Page(s): 3331 - 3337
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1289 KB) |  | HTML iconHTML  

    Two designs for compact continuously tunable phase shifters are presented employing integrated ferroelectric varactors based on screen-printed barium-strontium-titanate thick film. The circuits are based on left-handed transmission-line topologies that allow to realize very compact modules. The proposed designs have total lengths of 2.1 and 3.8 mm and provide a differential phase shift of more than 360° and a figure of merit of 51°/dB at 10 GHz. Furthermore, the phase shifters are in coplanar strip configuration, making them attractive for systems composed of balanced components. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generalized TM Dual-Mode Cavity Filters

    Publication Year: 2011 , Page(s): 3338 - 3346
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1982 KB) |  | HTML iconHTML  

    A new cavity arrangement, namely, the generalized TM dual-mode cavity, is presented in this paper. In contrast with the previous contributions on TM dual-mode filters, the generalized TM dual-mode cavity allows the realization of both symmetric and asymmetric filtering functions, simultaneously exploiting the maximum number of finite frequency transmission zeros. The high design flexibility in terms of number and position of transmission zeros is obtained by exciting and exploiting a set of nonresonating modes. Five structure parameters are used to fully control its equivalent transversal topology. The relationship between structure parameters and filtering function realized is extensively discussed. The design of multiple cavity filters is presented along with the experimental results of a sixth-order filter having six asymmetrically located transmission zeros. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Generalized Multiport Waveguide Switches Based on Multiple Short-Circuit Loads in Power-Divider Junctions

    Publication Year: 2011 , Page(s): 3347 - 3355
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1627 KB) |  | HTML iconHTML  

    This paper presents a new concept for multiport waveguide switches based on short-circuit loads integrated in power-divider ridge-waveguide junctions. The switching is achieved by means of actuating short and open circuit loads in the waveguide path of a ridge waveguide, eliminating the need of bulky rotors, which are typically used in conventional waveguide switches. A complete class of single-pole N -throw switches (N up to 4) is presented based on this concept. Furthermore, the concept is employed to demonstrate highly compact C-, R-, and T-type waveguide switches by integrating different power-divider junctions in a seamless manner. The T-type case involves three states that provide the maximum flexibility for realizing advanced switch matrices for signal routing. A T-type waveguide switch is built and measured for validating the concept. To our knowledge, this paper marks the first time R- and T-type waveguide switches are demonstrated without the need to use a bulky rotary junction. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Chipless RFID Tag Using Hybrid Coding Technique

    Publication Year: 2011 , Page(s): 3356 - 3364
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1241 KB) |  | HTML iconHTML  

    Increasing the coding capacity of chipless RFID tags is a key factor while considering the development of miniaturized tags. A novel hybrid coding technique by combining phase deviation and frequency position encoding is proposed here. A coding capacity of 22.9 bits is obtained simply with five resonators within a reduced dimension of 2 cm × 4 cm. The proposed tag is based on 5 `C' like metallic strip resonators having resonance frequency within the band of 2.5 GHz to 7.5 GHz. The tag is potentially low-cost since only one conductive layer is needed for the fabrication. Different tag configurations are designed and validated with measurement results in bi-static configuration. A good agreement between measurement and simulation validates the theoretical predictions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Waveguide Antenna Feeders With Integrated Reconfigurable Dual Circular Polarization

    Publication Year: 2011 , Page(s): 3365 - 3374
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2038 KB) |  | HTML iconHTML  

    Waveguide antenna feeders with reconfigurable circular polarization sense are proposed in this paper. They can be switched between right and left hand circular polarization, without any mechanical rotation between the feeder and the antenna. Two types of feeders are presented. The polarizer works with a single switchable polarization for each state. The dual feeder can work with both polarizations at the same frequency band simultaneously, each one associated with a different rectangular waveguide port. The polarization sense is controlled by metallic posts that block or open the signal paths connecting the rectangular ports with a septum-orthomode polarizer. These posts are automated with piezo-motors integrated in the structure, leading to a very compact layout, reduced size, and practical for applications with diverse switching speed. The proof of concept and the automation are shown with experimental Ku-band prototypes. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel Dual-Mode Retrodirective Array Using Synthesized Microstrip Lines

    Publication Year: 2011 , Page(s): 3375 - 3388
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2642 KB) |  | HTML iconHTML  

    In this paper, an innovative architecture for realizing a dual-mode retrodirective array (RDA) is proposed and experimentally validated. The new design functions as a reflection-type RDA in one frequency band and features the characteristics of a Van Atta array in the other band. A unique 50-Ω synthesized microstrip line is applied to fulfill the core building blocks of this RDA, i.e., the dual-mode quadrature hybrids and crossovers. Both couplers show equivalent responses to their conventional counterparts in the low-frequency band, but enable direct-thru transmission properties in the high band. To validate this innovative architecture, a four-element dual-mode RDA is fabricated and experimentally verified. The measured bistatic radiation patterns provide supportive evidence to the dual-band self-steering capability of the proposed array. The circuit topologies, design approaches, system considerations, and simulated and measured results are investigated in detail throughout this paper. Suggestions to improve the system performance are discussed as well. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tunable Inter-Resonator Coupling Structure With Positive and Negative Values and Its Application to the Field-Programmable Filter Array (FPFA)

    Publication Year: 2011 , Page(s): 3389 - 3400
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1288 KB) |  | HTML iconHTML  

    In this paper, we show a tunable inter-resonator coupling structure capable of varying the coupling coefficient between resonators from positive to negative values, including values that approach zero. The presented inter-resonator coupling structure can be tuned to generate large isolation between two resonators as well as the required coupling for filter responses. Using the inter-resonator coupling structure, this paper demonstrates the concept of a field-programmable filter array (FPFA). The proposed array is composed of tunable resonators and can have multiple functionalities by routing signals from input ports to output ports. Signal routing can be achieved by controlling the inter-resonator coupling with a wide tuning ratio of coupling coefficients. A unit cell of the proposed FPFA was fabricated to prove the proposed concept. It is shown that the unit cell can be adjusted to have filter array responses with two second-order bandpass responses, third-order bandpass responses, and fourth-order bandpass responses. The unit cell can also be operated as a switchable filter bank without a switch. All operation modes are verified by measurements. This paper also demonstrates, for the first time, a reconfigurable filter that can be tuned to have both elliptic and self-equalized responses using the presented inter-resonator coupling structure. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High- Q Tunable Dielectric Resonator Filters Using MEMS Technology

    Publication Year: 2011 , Page(s): 3401 - 3409
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2639 KB) |  | HTML iconHTML  

    This paper presents the design and implementation of a new class of high-Q tunable dielectric resonator (DR) filters based on microelectromechanical systems (MEMS) technology. The use of MEMS tuning elements results in the compact implementation of the proposed filters with high-Q and near to zero dc power consumption. The proposed filters consist of disk-shaped dielectric resonators with circular holes created in the center of each resonator. Three different filters are designed and measured based on different tuning elements. The first filter operates in TME mode at a center frequency of 4.72 GHz with a bandwidth of 21 MHz. MEMS contact-type switches are used as tuning elements for this filter. Measurement results demonstrate a tuning range of 160 MHz while the quality factor is above 510 (1200-510 over the tuning range). The other two implementations employ GaAs and MEMS varactors for tuning. The tunable filter with GaAs varactor has a continuous tuning range from 4.97 to 4.87 GHz with 65-MHz bandwidth and a Q value from 660 to 170. The MEMS varactor-tuned filter has a better tuning performance from 5.20 to 5.02 GHz with higher Q value from 800 to 550 over the tuning range. The proposed tuning approach is applicable to other modes at other frequencies of DR filters. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Parylene Interposer as Thin Flexible 3-D Packaging Enabler for Wireless Applications

    Publication Year: 2011 , Page(s): 3410 - 3418
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1050 KB) |  | HTML iconHTML  

    This paper presents a novel, all-Parylene, thin, flexible 3-D packaging technology with an application demonstration of wireless powering. Parylene is utilized as a base substrate of a packaging interposer, and multilayer thin films are conformally stacked on the Parylene substrate. High-density (450 pF/mm2) metal-insulator-metal capacitors are implemented with an ultrathin (~47 nm) deposition of Parylene-N. The energy storage capabilities as well as RF characteristics are characterized. To demonstrate interposer applicability, an RF energy-harvesting study is performed by implementing a rectifier circuit on the Parylene interposer utilizing embedded capacitors of wide-ranging values and an antenna. Finally, substrate folding tests are performed to verify the applicability of the Parylene interposer in a flexible form factor without undergoing degradation in energy-harvesting capability. The thin-film flexible capacitors are demonstrated to not short-circuit even under the stress of folding the interposer. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Linearity Characterization and Optimization of Millimeter-Wave GaN HEMTs

    Publication Year: 2011 , Page(s): 3419 - 3427
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2010 KB) |  | HTML iconHTML  

    This paper presents the first comprehensive study of the linearity characteristics of GaN/SiC high-electron mobility transistors (HEMTs) at millimeter-wave (mmW). Similar size devices from three sources are compared using AM-AM, AM-PM, two-tone, and 16-quadrature-amplitude modulation (16QAM) modulated waveforms measurements at 31.5 GHz. Additionally, error vector magnitude (EVM) and spectrum regrowth [adjacent channel power ratio (ACPR)] data are also presented. The results were measured, using a unique digital waveform system integrated with a mmW (50-GHz) load-pull system, for HEMTs at different classes of operation: A, AB, and B. In all devices, it is observed that a “balanced AB” (b-AB) class of device bias condition where linearity and efficiency are simultaneously optimized. A linearity figure of merit FOMlinearity, based on single-tone power measurements, is defined and calculated for each class. The FOMlinearity closely correlates with linearity performance of the HEMT under two-tone and digitally modulated drive conditions. Compared with class A, at a fixed output power, a b-AB class showed a 5-10-dB improvement in intermodulation distortions, combined with 1.2 × to 1.9 × enhancement in drain efficiency. The characterization methodology and derived FOMlinearity should benefit monolithic microwave integrated circuit (MMIC) designers to optimize the operation of GaN HEMTs. The results also indicate that GaN HEMTs can provide linearity characteristics suitable for applications such as satellite communications, while maintaining high efficiency and power density. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimized Design of Pulsed Waveform Oscillators and Frequency Dividers

    Publication Year: 2011 , Page(s): 3428 - 3440
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1952 KB) |  | HTML iconHTML  

    A technique is presented for the optimized design of oscillators and frequency dividers based on nonlinear transmission lines (NLTLs). The oscillator design relies on a closed-loop configuration containing a high-efficiency amplifier, with the loop output matched to a short NLTL. Attention is paid to the oscillator phase noise. A simple and general-application method is presented for an accurate calculation of the phase sensitivity functions with respect to specific noise sources. The predictions obtained when considering stationary and cyclo-stationary noise-source models are compared. The influence of crucial design parameters on the oscillator efficiency, pulse amplitude, and duty cycle is analyzed, as well as their impact on the phase-noise behavior. An efficient simulation technique enables the evaluation of the injection-locking capabilities during this global optimization of the oscillator in the free-running regime. The phase-noise spectrum in injection-locked conditions is analyzed in detail, considering the influence of flicker noise. A frequency division by 2 is observed in the amplifier stage loaded by the NLTL. The origin of this division is investigated, as well as the influence of the number of cells on the pulsed waveform and the division bandwidth. The techniques have been successfully applied to the design of a pulsed oscillator at 900 MHz. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis and Design of Millimeter-Wave Low-Power CMOS LNA With Transformer-Multicascode Topology

    Publication Year: 2011 , Page(s): 3441 - 3454
    Cited by:  Papers (10)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1833 KB) |  | HTML iconHTML  

    In this paper, the analysis and design of a CMOS multicascode configuration with a noise-reduction transformer topology are presented. Two low-power (LP), miniature, and wideband low-noise amplifiers (LNAs) were designed and fabricated for demonstration. One with a transformer triple-cascode configuration was designed at V-band, and the other with a transformer quadruple-cascode configuration was designed at Q-band. Both of the two LNAs were fabricated using 90-nm LP CMOS technology. To minimize the noise figure (NF) and maximize both the small-signal gain and 3-dB bandwidth, the noise-reduction transformers are designed and placed between transistors of the triple- and quadruple-cascode devices. Based on this approach, the Q-band LNA has a gain of 20.3 dB and an NF of 4.6 dB at 40 GHz, with a power consumption of 15 mW. Both of the LNA utilize a 3-V supply voltage, but the drain source voltage of each device in the multicascode configuration is below 1 V. The V-band LNA presents a gain of 12.7 dB from 43 to 58 GHz and a minimum NF of 4.7 dB at 62.5 GHz with a power consumption of 18 mW. The chip size of the V- and Q -band LNAs are 0.42×0.45 mm2 and 0.45×0.48 mm2, including all the testing pads. Compared with the conventional cascode LNAs, the proposed transformer triple-cascode LNA has a better NF, wider 3-dB bandwidth, and lower power consumption, whereas the transformer quadruple-cascode LNA features even higher gain performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • ESD-Protected K-Band Low-Noise Amplifiers Using RF Junction Varactors in 65-nm CMOS

    Publication Year: 2011 , Page(s): 3455 - 3462
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1374 KB) |  | HTML iconHTML  

    This paper presents two K-band low-noise amplifiers (LNAs) in 65-nm CMOS using the proposed RF junction varactors as the ESD protection devices. The junction varactors are customized for the RF ESD applications with accurate equivalent circuit models. The experimental results demonstrate excellent second breakdown currents (It2) and high ratios of the ESD level to parasitic capacitances (VESD/CESD) . Using the dual-diode topology, the first LNA demonstrates an over 2-kV Human-Body-Model (HBM) ESD protection level with a noise figure (NF) of 2.8 dB and a peak gain of 14.3 dB at around 24 GHz under a power consumption of only 7 mW. By incorporating an RF junction varactor as the extra gate-source capacitance at the input stage as a part of the ESD network, the second LNA presents an enhanced failure current level up to 2.6 A (corresponding to an HBM ESD level of 3.9 kV), and a Charge-Device-Model (CDM) ESD level up to 10.7 A, characterized by the Very Fast Transmission Line Pulse (VFTLP) tests. The second LNA shows a NF of 3.2 dB and a power gain of 13.7 dB, also under 7 mW. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Multimode/Multiband Envelope Tracking Transmitter With Broadband Saturated Amplifier

    Publication Year: 2011 , Page(s): 3463 - 3473
    Cited by:  Papers (17)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2453 KB) |  | HTML iconHTML  

    A multimode/multiband envelope tracking (ET) transmitter consisting of a hybrid switching amplifier (HSA) and a broadband saturated power amplifier (PA) is developed for operation across 1.3 to 2.7 GHz. For the various standard signals with different bandwidth (BW) and peak-to-average power ratio, the HSA efficiently provides supply signals to the PA by changing the reference value of the hysteresis comparator. The saturated amplifier employs the nonlinear output capacitor to shape the voltage waveform, resulting in the half-sinusoidal or rectangular waveform. Since the nonlinear capacitor generates large out-of-phased second harmonic component with small higher order harmonics, the voltage shaping is mainly carried out by the capacitor and slightly supported by the harmonic loading circuit. Thus, with the harmonic load higher than that of output capacitor, the saturated amplifier can operate with high efficiency. This characteristic enables the saturated PA to operate with broadband characteristic and high efficiency because the design is mainly focused on the fundamental matching problem while the harmonics can be easily kept out of a low efficiency region through the subsequent optimization of the matching circuit. The broadband saturated PA is implemented based on load/source-pull methodology. The broadband matching networks for the high efficiency are synthesized using the simplified real frequency technique. For the BW from 1.3 to 2.7 GHz (70% fractional BW), the measured output power, drain efficiency, and power-added efficiency (PAE) performances are between 39.8-42.0 dBm, 55.8-69.7%, and 51.2-65.3%, respectively. The multimode/multiband ET transmitter with the designed broadband saturated PA is demonstrated at 1.8425-GHz long-term evolution (LTE), 2.14-GHz wideband code division multiple access (WCDMA), and 2.6-GHz mobile world wide interoperability for microwave access (m-WiMAX) applications. This transmitter delivers a PAE of 32.16, 37.24, and 28.75% for - - LTE, WCDMA, and m-WiMAX applications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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

Meet Our Editors

Editor-in-Chief
Dominique Schreurs
Dominique.Schreurs@ieee.org

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