International Journal
1993 documents found.
High-frequency monolithic thin-film piezoelectric-on-substrate filters
Published online : 01-02-2009
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A class of micromachined acoustic filters is presented in which the number of individual resonant structures is reduced to 1 (monolithic filter). This resonant structure is comprised of a stack of thin-film piezoelectric-on-silicon. Symmetric and anti-symmetric resonance modes (dual modes) of the silicon structure are piezoelectrically excited and coupled to realize a 2-pole narrowband filter. Hig
Lithographical bending control method for a piezoelectric actuator
Published online : 01-02-2009
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This paper presents the theoretical formulation of a lithographical bending control (LBC) method that uses lithographical degrees of freedom to control the bending of a multilayered beam. LBC is applied to a piezoelectric actuator that uses PZT as the piezoelectric material. The theoretical model is compared with measurements using a weakly fixed bridge structure suited for curvature measurement.
Experimental system level analysis of a concurrent dual-band power amplifier for WiMAX and WCDMA applications
Published online : 01-04-2009
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This paper presents a feasibility study for the implementation of a concurrent dual-band power amplifier (PA) design suitable for 1.98 GHz WCDMA and 3.42 GHz WiMAX digital systems. The proposed PA design was compared with a test bed based on a pair of dedicated single-frequency band PAs. The dual-band PA exhibited simultaneous peak output power levels of 24 and 17 dBm in the lower and in the highe
Concurrent dual-band SiGe HBT power amplifier for Wireless applications
Published online : 01-04-2009
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This paper presents an investigation of a concurrent low-cost dual-band power amplifier (PA) fabricated in SiGe technology, able to simultaneously operate at two frequencies of 2.45 and 3.5-GHz, including an evaluation of its system level performance potentiality. Taking into account the technology novelty and the lack of device characterization and modeling, a hybrid (MIC) approach has been adopt
Behavioral modeling and linearization of a millimeter-wave power amplifier
Published online : 01-04-2009
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The use of digital predistortion for linearizing a millimeter-wave power amplifier (PA) is investigated. A PA operating at 38 GHz is designed using an accurate non-quasi-static transistor model, taking into account both short- and long-term memory effects. A realistic test signal is then used for the identification of a nonlinear auto-regressive moving average (NARMA) behavioral model of the PA. T
Nonlinear modeling of InP devices for W-band applications
Published online : 01-04-2009
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A recently proposed technique for the distributed modeling of extrinsic parasitic effects in electron devices is used for the very first time in conjunction with a lumped equivalent circuit model for the intrinsic device.
Nonideality sources and implementation considerations in polar transmitters
Published online : 01-04-2009
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In this paper, the main nonidealities appearing in polar transmitters will be addressed, together with several implementation considerations. Special attention will be paid to the role of AM modulation nonlinearity and parasitic AM-to-PM conversion, once architecture mechanisms such as time-delay mismatch between branches or limited bandwidth in the amplitude path are controlled. The device limiti
A semi-lumped microstrip UWB bandpass filter
Published online : 01-02-2009
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In this paper, a miniaturized bandpass filter for ultra-wide-band applications is proposed. It is based on the embedding of high-pass structures in a low-pass filter. A semi-lumped technology combining surface-mounted capacitors and transmission lines has been used. The filter design rules have been carried out. Furthermore, two filters having a 3-dB fractional bandwidth of 142 and 150%, centered
Mitigation of wideband interference on UWB-IR transmission using multi-carrier templates
Published online : 01-02-2009
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Ultra wideband (UWB) wireless systems are highly susceptible to interference from other services. To reduce the effect of interference from co-existing sources such as the WLAN standard IEEE 802.11a on UWB Communication, the construction of a modified template waveform using multi-carrier sinusoids is proposed in Ohno and Ikegami (2003), Ohno et al. (2004), Ohno and Ikegami (2006), and Lakshmanan
Criteria for the evaluation of linear two-port stability using two geometrically derived parameters
Published online : 01-02-2009
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Two geometrically derived stability parameters, µ? (or µ) and ??(or ?), are used to analyze the stability of a two-port network. The magnitudes of both µ? (or µ) and ?? (or ?) parameters determine geometrical relations between the stability circle and the unit Smith chart in the (or ) plane. |µ?| (or |µ|) is defined as the minimum distance from the stability circle to the origin of the unit Smith