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High signal to noise ratio (SNR) in magnetic resonance imaging is vital for ensuring accurate diagnosis and treatment. Arrays of surface coils for receive only purposes is a well established way to increase SNR. However, due to crosstalk between the array elements, the SNR can be severely degraded. For that reason, arrays often do not exploit their full potential. By using a series decoupling network...
A concurrent triple-band digital transmitter architecture with relaxed RF output filter requirement is presented in this paper. With non-contiguous inter-band carrier aggregation, all digital transmitters based on delta-sigma modulation and pulse-width modulation have suffered from out-of-band noise and spurious tones, requiring extremely demanding RF output filter design. We demonstrate a feedforward...
In this paper, a 60 GHz double receive channel FMCW transceiver measurement results together with the design procedure and simulations are presented, considering the license free ISM band. 0.13μm SiGe BiCMOS technology having 250/340 GHz of fr/fmax is utilized to fabricate this fully integrated chip with a die area of 1.65 × 1.05 mm2. The chip is composed of two receiver channels including I/Q based...
A charge-controlled, one-port device is used to describe and discuss the extraction procedure of a Poly-Harmonic Distortion (PHD) model in detail. For this case, both voltage and current waveforms are shown to be enough to fully characterize the PHD model. It is also shown that all the information specifically required for this PHD model definition can be stored in the Fourier coefficients of the...
This paper presents a broadband integrated doublebalanced I/Q-upconverter at 73.5 GHz in a 50 nm InGaAs-based metamorphic high electron mobility transistor technology including Lange couplers with voltage-controlled variable termination resistance. The variable resistance is implemented by using resistive FETs. This MMIC is designed for broadband communication with controllable LO suppression at the...
A novel substrate-less oscillator module realized by gap waveguide technology is proposed in Ka band. No substrate is used in the RF section of the implemented oscillator and the whole structure is made by machining a piece of metal. The oscillator was made of three pieces and was assembled easily without needing a precise contact between them. Active device and the resonator of the oscillator are...
The design and performance of a compact 6–18GHz power amplifier MMIC utilizing 0.2 pm gallium nitride (GaN) high electron mobility transistor (HEMT) technology is presented. An output power of 41.4 dBm to 43.3 dBm (average 42.3dBm) with over 16 dB power gain and a power added efficiency (PAE) of 21% to 35% over the band of 6–18 GHz under a drain voltage of 28 V in CW mode have been achieved. The chip...
In this work the design of a Ku-band reconfigurable phase shifter implemented in waveguide technology is presented. The reconfiguration capability of the device is achieved by the insertion of a pair of adjustable metallic posts. A prototype of this device has been manufactured using a 3D printing technique in order to show the proposed concept. The measured return loss and phase performances of this...
A 30 GHz liquid-crystal-based amplitude tuner is proposed for the first time. The amplitude of a signal can be controlled by using the interference principle. An input signal is divided into a tunable liquid crystal phase shifter and a fixed transmission line. Later, the divided signals are combined together at the output port. The output amplitude depends on the phase difference between the tunable...
In this paper, a low-loss and high-selectivity compact CMOS bandpass filter at S band is presented. The filter based on lumped elements achieves low insertion loss and ultrawide bandwidth. Moreover, the resonators of the filter result in two finite transmission zeros. One transmission zero is in the lower stopband, and the other is in the upper stopband, thus improving the selectivity of the filter...
In this paper, the authors present proof of concept 3D printed interconnects fabricated using aerosol jet printing (AJP) technology. A trapezoidal structure was 3D printed on Liquid Crystal Polymer (LCP) and Coplanar Waveguides (CPW) were printed on top of them to imitate mm-wave packaging. The printing was done using silver nanoparticle ink that acquired 40% conductivity of the bulk silver after...
In the paper, experimental results of a novel dualband DPD model based on CPWL functions [4] are provided. With the feature of CPWL functions that is a minimal formulation requiring minimal amount of memory to store the parameters, the CPWL-based DPD model can release the requirement for huge number of coefficients for concurrent dual-band DPD systems. Our test results show the CPWL-based DPD model...
This paper studies the impact of gain scaling on linearization performance and power added efficiency (PAE) of a power amplifier (PA) using digital predistortion (DPD). The performance of the DPD designed at different operating points of PA with different choices of gain are compared. An adjustment in iterative DPD identification procedure is proposed to improve the convergence. The performances are...
This paper describes a new instantaneous wideband predistortion linearizer for TWTA enabling to use simultaneously broadband multi-carrier signals all over the complete 17.3–20.2GHz transmit Ka-band for the new generation of Telecom satellite. The linearizer has been embedded in a space equipment and successfully tested with a wideband Ka-band space TWTA. A state-of-the-art NPR performance was obtained...
Models for active devices operating in a nonlinear regime are an indispensable tool for modern RF-circuit design. A popular class of large signal models are X-parameters which offer an accurate description of nonlinear devices. However, they require a specialized measurement setup. Typically nonlinear vector network analyzers (NVNA), are used to conduct the measurements required for an X-parameter...
A powerful new technique is presented and used to derive compact closed-form expressions for the optimum output reflection coefficient for maximum power transfer to the load of a PA under large-signal input drive. Wirtinger calculus is applied to a non-analytic X-parameter expression to formulate the extremal problem in a form that can be solved exactly, by hand, in explicit form. Compact formulas...
In this paper an electromagnetic (EM) simulation assisted parameters extraction procedure is demonstrated for accurate modeling of down-scaled transferred-substrate InP HBTs. The external parasitic network associated with via transitions and device electrodes is carefully extracted from calibrated 3D EM simulations up to 325 GHz. Following an on-wafer multi-line Through-Reflect-Line (TRL) calibration...
This paper reports on a Voltage-Controlled-Oscillator (VCO) chip set covering 7–13 GHz with phase noise better than −125 dBc/Hz at 1 MHz off-set. The chip set is implemented in GaN HEMT MMIC technology and designed for use in satellite transponders. 6 VCOs are used to cover the full range, each of them has tuning range about 1 GHz with output power in the order of 5 dBm. GaN HEMT technology is chosen...
GaN low-noise amplifiers need to provide low noise figure, but are also often expected to be highly rugged. This paper addresses the question, how HEMT devices within a certain technology can be optimized only by changing basic geometrical properties. While epitaxial layer structure and gate length usually are not accessible, the circuit designer might be able to choose parameters as gate finger width...
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