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Microwave and Wireless Components Letters, IEEE

Issue 5 • Date May 2001

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Displaying Results 1 - 13 of 13
  • An efficient HBT/RTD oscillator for wireless applications

    Publication Year: 2001 , Page(s): 193 - 195
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (53 KB) |  | HTML iconHTML  

    In this paper, we introduce a novel HBT/RTD oscillator suitable for monolithic integration and efficient low power/battery-operated applications. Implementation of a circuit prototype was accomplished by configuring an InP-based monolithic HBT/RTD chip with a gold wire bond inductor in a hybrid microwave package. For an output frequency of 5.8 GHz, the circuit draws a current of 15.5 mA from a 1.5 V supply and generates an output power of +3.13 dBm, for an efficiency of 8.84%. View full abstract»

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  • Effects of nonlinear diode junction capacitance on the nose-to-nose calibration

    Publication Year: 2001 , Page(s): 196 - 198
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (54 KB) |  | HTML iconHTML  

    We examine the effects of nonlinear diode junction capacitance on the fundamental premise of the nose-to-nose calibration, that the kickout pulse is identical in shape and duration to the impulse response of a sampling circuit. We offer a physical explanation for the error introduced by the nonlinear junction capacitance using small-signal diode equations. View full abstract»

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  • A fully-integrated low-power low-noise 2.6-GHz bipolar VCO for wireless applications

    Publication Year: 2001 , Page(s): 199 - 201
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (63 KB) |  | HTML iconHTML  

    The low quality factor of the inductors fabricated in fully-integrated LC tanks results in a poor indirect stability of the oscillators, which are therefore highly sensitive to low-frequency noise and disturbances coupled through substrate and supply lines. The paper addresses the design of a 2-V voltage-controlled oscillator (VCO) at 2.6 GHz fabricated in a Si-bipolar process with f/sub T/ of 20 GHz. The circuit bias and the transistor layout have been specifically optimized to minimize the phase noise degradation due to the intrinsic low indirect stability. A single sideband-to-carrier ratio (SSCR) of -104 dBc/Hz at 100 kHz is demonstrated with less than 14 mW power consumption. View full abstract»

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  • Novel oscillator incorporating a compact microstrip resonant cell

    Publication Year: 2001 , Page(s): 202 - 204
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (55 KB) |  | HTML iconHTML  

    A novel transistor oscillator incorporating a compact microstrip resonant cell (CMRC) as its terminating resonance is proposed. Adjusting the dimensions of the cell, it is possible that the fundamental frequency can be positively fed back and the second harmonic negatively fed back at the input port of the oscillator. The fundamental output is enhanced with the second harmonic being suppressed. The output power of the proposed CMRC oscillator is 14.7 dBm at 2.5 GHz with 27.1 dB rejection of the second harmonic, outperforming the conventional microstrip termination with a 40% size reduction. View full abstract»

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  • High performance dual directional couplers for near-mm wavelengths

    Publication Year: 2001 , Page(s): 205 - 207
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (50 KB) |  | HTML iconHTML  

    A low loss, high directivity dual directional coupler has been developed suitable for fabrication in waveguide bands up to WR3 (220-325 GHz). The design uses waveguide split on the E plane centerline with three waveguides running side by side and coupling holes made by drilling through all three guides. Construction is relatively simple and the resulting structure is very robust mechanically. Typical coupling is 15 dB, directivity is 25-30 dB, and the insertion loss of the WR3 coupler is 0.5 dB. View full abstract»

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  • Novel low-cost ultra-wideband, ultra-short-pulse transmitter with MESFET impulse-shaping circuitry for reduced distortion and improved pulse repetition rate

    Publication Year: 2001 , Page(s): 208 - 210
    Cited by:  Papers (40)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (40 KB) |  | HTML iconHTML  

    A new ultra-wideband, ultra-short-pulse transmitter has been developed using microstrip lines, step-recovery and Schottky diodes, MESFET, and monolithic microwave integrated circuit (MMIC) amplifier. This transmitter employs a novel MESFET impulse-shaping circuit to achieve several unique advantages, including less distortion, easy broadband matching, and increased pulse repetition rate. The transmitter produces 300-ps monocycle pulses with about 2 V peak-to-peak and a pulse repetition rate of 10 MHz. The measured pulses have good symmetry and low ringing level. View full abstract»

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  • A new finite element model for reduced order electromagnetic modeling

    Publication Year: 2001 , Page(s): 211 - 213
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (62 KB) |  | HTML iconHTML  

    This paper introduces a new formulation suitable for direct model order reduction of finite element approximations of electromagnetic systems using Krylov subspace methods. The proposed formulation utilizes a finite element model of Maxwell's curl equations to generate a state-space representation of the electromagnetic system most suitable for the implementation of model order reduction techniques based on Krylov subspaces. It is shown that, with a proper selection of the finite element interpolation functions for the fields, the proposed formulation is equivalent to the commonly used approximation of the vector wave equation with tangentially continuous vector finite elements. This equivalence is exploited to improve the computational efficiency of the model order reduction process. View full abstract»

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  • Cutoff wavenumbers in truncated waveguides

    Publication Year: 2001 , Page(s): 214 - 216
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (59 KB) |  | HTML iconHTML  

    Truncated waveguides are used in some microwave components. The cutoff wavenumbers in truncated circular waveguide and truncated square waveguide are desired but usually difficult to be computed. In this paper, they are efficiently determined using the unified method that we proposed earlier. Both TE-polarized and TM-polarized modes are studied. To demonstrate the applicability and correctness of this method, two practical examples are considered, one is a truncated circular waveguide and the other is a truncated square waveguide. Results obtained for the two cases are compared with existing data in literature and a good agreement is observed. A further extension of the work is made to compute cutoff wavenumbers of a truncated elliptical waveguide. It is found from the analysis that the cutoff wavenumbers in these irregular waveguides can be computed easily, rapidly, and accurately using the unified method. View full abstract»

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  • Optical fiber recirculating delay line incorporating a fiber grating array

    Publication Year: 2001 , Page(s): 217 - 219
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (53 KB) |  | HTML iconHTML  

    For a practical optical fiber recirculating delay line the maximum notch depth and tunable free spectral range are difficult to achieve because of fixed coupling coefficient and loop length. We present here an optical fiber recirculating delay line incorporating a fiber grating array. In this work, the effect of insertion loss in the delay loop is investigated and used to maximize the notch depth of the frequency response. The tunable free spectral range is obtained from the wavelength dependent loop length introduced by the fiber grating array. View full abstract»

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  • Time-domain finite-element modeling of dispersive media

    Publication Year: 2001 , Page(s): 220 - 222
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (78 KB) |  | HTML iconHTML  

    A general formulation is described for time-domain finite-element modeling of electromagnetic fields in a general dispersive medium. The formulation is based on the second-order vector wave equation and incorporates the dispersion effect of a medium via a recursively evaluated convolution integral. This evaluation is kept to second order in accuracy using linear interpolation within each time step. Numerical examples are given to validate the proposed formulation. View full abstract»

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  • Computation of resonant frequencies and quality factors of cavities by FDTD technique and Pade approximation

    Publication Year: 2001 , Page(s): 223 - 225
    Cited by:  Papers (75)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (59 KB) |  | HTML iconHTML  

    The finite-difference time domain (FDTD) technique and the Pade approximation with Baker's algorithm are used to calculate the mode frequencies and quality factors of cavities. Comparing with the fast Fourier transformation/Pade method, we find that the Pade approximation and the Baker's algorithm can obtain exact resonant frequencies and quality factors based on a much shorter time record of the FDTD output. View full abstract»

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  • A fast PEEC technique for full-wave parameters extraction of distributed elements

    Publication Year: 2001 , Page(s): 226 - 228
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (87 KB)  

    In this paper, a full wave partial element equivalent circuit (PEEC) technique using exact Green's function is introduced for the parameter extraction of a passive device in a homogeneous media over a wide frequency range from de to a frequency of interest. This technique makes use of some analytical techniques and cartesian multipole expansion to derive simple closed form expressions for each individual element of the coupling matrices that commonly arise in integral equation algorithms, in terms of the wave number alone. Hence, these matrices can be reused each time a new frequency is selected. As simple closed form expressions are used, very fast computation is possible. View full abstract»

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  • Patent abstracts

    Publication Year: 2001 , Page(s): 229 - 237
    Save to Project icon | Request Permissions | PDF file iconPDF (206 KB)  
    Freely Available from IEEE

Aims & Scope

The IEEE Microwave and Wireless Components Letters (MWCL) publishes three page papers that focus on microwave theory, techniques and applications as they relate to components, devices, circuits, biological effects, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals.

Full Aims & Scope