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A microstrip differential-mode (balanced) bandpass filter covering the frequency spectrum assigned for ultra-wideband (UWB) communications (3.1GHz–10.6GHz) is presented. The main relevant characteristics of the proposed filter are: (i) the good stop band performance above the band of interest, with high selectivity, harmonic suppression and broad rejection bandwidth, achieved thanks to the embedded...
We present a semi-analytical model for dense vias in an infinite parallel-plate environment with a shared-antipad configuration. The network parameters are estimated based on reciprocity. The field from the reciprocal source is highly localized, making the mode matching computation converge very fast. In addition, the near field can be expressed in a closed-form, making the method computationally...
A single-chip 45 GHz power amplifier implemented in 45nm CMOS SOI is described, which feeds its RF output power to a 2×2 antenna array on an accompanying printed circuit board. The chip results in a maximum RF output power of 28 dBm (630 mW), and the system achieves a peak equivalent isotropic radiated power (EIRP) of 10 Watts (for a 2×2 antenna gain of 12 dB). The power amplifier is composed of 4...
A fully printable 60 GHz chipless RFID tag provides high data capacity. The printed tag consists of an array of 45° inclined conductive microstrips that act as perfect electromagnetic (EM) polarizers. When illuminated with a linearly polarized signal, the tag's backscattered cross - radar cross section (RCS) response is much larger than its co-RCS. The tag can encode up to 50 bits of binary data in...
This paper presents a fully integrated CMOS power amplifier (PA) with a dynamic feedback and gate biasing. The two dynamic circuits improve the linearity and efficiency of the stand-alone PA and ET PA. The proposed CMOS ET PA including the dynamic control circuits is fabricated using 0.18-μm CMOS process. For a long-term evolution (LTE) signal at 1.85 GHz with a 10-MHz bandwidth and a 16-QAM 7.5 dB...
This paper presents a memory of the author's interaction with Professor Arthur A. Oliner in regard to hidden phenomena of leakage from certain dielectric waveguide structures. These phenomena are very mild so that they can be revealed only by his insight backed by a rigorous analysis and physical understanding of guided waves. He found mistakes in the author's work but it is not fatal. However, this...
In this paper a CMOS biosensor array operating around 8 GHz is presented, for characterizing biomaterials by imaging the spatial distribution of permittivity. The sensor is fabricated in standard 250 nm SiGe BiCMOS process. The sensor operation is based on the frequency shift of cross-coupled oscillator circuit due to capacitance change of the core LC tank. Non-uniform four finger interdigitated capacitor...
A frequency-tunable lens-coupled annular-slot antenna using a Schottky varactor diode has been developed and characterized at 140–220 GHz. A tuning range of ∼50 GHz (agree with simulation) has been demonstrated by varying the diode's DC bias. Antenna far-field patterns have been measured at 203 GHz, showing that the diode has only a minor effect on the antenna's radiation properties. This type of...
Digital predistortion (DPD) is one of the most effective techniques to mitigate the power amplifier (PA) nonlinear distortion. The DPD feedback bandwidth is often restricted by the nonideal electronic components, e.g., the anti-aliasing filter, which introduces bandwidth mismatch between model basis function and feedback signal thus degrades the linearization performance. This paper presents a new...
This paper proposes an integrated reflectometer for biomedical sensor read-out applications using a low-cost silicon-germanium technology. The heterodyne reflectometer consists of two integrated cross-coupled oscillators, a set of two directional couplers as well as Gilbert-Cell downconversion mixers. A dual phase-locked-loop architecture guarantees the phase lock of both on-chip signal sources to...
A compact, high-selectivity, and high-isolation microstrip quad-channel diplexer has been presented in this paper. By introducing multiple coupling paths between input and output ports, the diplexer design is, therefore, more flexible and can be extended to higher-order multiplexers. In addition, no extra matching network is needed for this design, resulting in a smaller circuit size. For the demonstration,...
A novel vertical stepped-impedance resonator (SIR) is proposed based on the conventional multi-layer printed-circuit board (PCB), exhibiting high unloaded quality factor (Q = 185), compact size and low electromagnetic (EM) coupling to nearby RF circuits. The proposed resonator is used in a 2–3 GHz 4-pole tunable bandpass filter. The resulting filter occupies a footprint of 13 mm × 15 mm and covers...
A modified Doherty combining scheme is proposed that eases the impedance matching requirement and enables excellent AM/AM, AM/PM, and wide bandwidth in practical designs. A 350 W, 790 to 960 MHz symmetrical LDMOS Doherty amplifier measured 20 to 21 dB gain as well as peak and back-off efficiencies of 56% to 61% and 48% to 50% respectively across the band. The amplifier achieved excellent linearization...
Prof. Arthur A. Oliner is probably best known in the technical world for his fundamental contributions to the field of leaky waves and leaky-wave antennas. Here we review some of his contributions in these areas, as seen from a personal perspective by the author.
This paper proposes an iterative calibration technique to enhance the linearity for multilevel LINC transmitters. With this approach, the precision of characterising AM/AM and AM/PM behaviours for discrete levels can be improved, which results in better adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) performance. An ML-LINC transmitter is built with two PAs in GaN technology,...
LTE-Advanced uses carrier aggregation (CA) of multiple component carriers (CCs) to achieve high-bandwidth transmission. To fulfill such technology, the novel carrier-aggregated modulator structure is proposed. In this work, the carrier-aggregated modulator is implemented in 0.18 µm CMOS technology and tested with two 10 MHz LTE-Advanced Release 10 signals to demonstrate the feasibility of the proposed...
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