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Cooperative spectrum sensing in cognitive radio (CR) avoids hidden terminal problems common to network architectures with central sensing nodes. It also lowers the requirements for the sensing radio front-ends. This paper presents a multi-chip module RF front-end implemented from custom RFICs realized in an 0.25 µm SiGe BiCMOS technology. Using an up/down-conversion heterodyne architecture, the front-end...
This paper presents a fast responding frequency measurement system based on Six-Port technology being able to determine precisely the frequency of very short time domain pulses of one microsecond and even less in the 2.4 GHz ISM band. By using a delay line the frequency measurement can be reduced to a phase measurement that can be quickly evaluated by the Six-Port network implemented with lumped components...
This paper presents the design, manufacturing and testing of a MEMS SP16T switch to be used in open loop reconfigurable antenna systems. It consists of the hybrid integration of #5 MEMS SP4T switches (realized on HR Silicon substrate) on a multilayer substrate. The bilayer structure allows one to avoid RF and DC signal crossovers that could degrade the switch performance. The device is provided with...
A 12×12 Switch Matrix Unit featuring silicon RF MEMS assembled on LTCC boards has been developed under a Contract with the European Space Agency (ESA) for satellite communication application. The Switch Matrix is a complete Engineering Model unit, housed in a mechanical box in aluminum with RF coaxial connectors and DC connectors for powering and commanding. To the authors' knowledge, it is the first...
A novel 8-mask fabrication process for the integration of Low Temperature Superconducting (LTS) niobium (Nb) RF circuits with gold-based RF MEMS switches is proposed. A fixed and a tunable 3-pole bandpass filter (BPF) are fabricated implementing the new Nb-based fabrication process. The tunable BPF includes nine dc-contact RF MEMS switches. The center frequency of the tunable BPF shifts from 10 GHz...
High Power handling capabilities are not the main focus in MEMS varactor research and development. In this paper MEMS varactors with excellent RF power handling capabilities of up to 16 VPP for application in low noise wideband RF VCOs (Voltage controlled oscillators) have been designed, fabricated and characterized. These MEMS varactors are embedded in the BEOL (Back end of line) metallization stack...
A new quad mode 2-way Microstrip reconfigurable power divider is presented. The proposed power divider, through the use of 4 or 6 switches, can alternate the operating mode between a total of 4 modes. The four operating modes are: totally directing the power into one of the two output ports (1∶0) & (0∶1) and two-way equal power split with + or − 90o phase shifts (1∶j) & (j∶1). Several dividers...
This paper evaluates a liability in use of modulated signal for microwave wireless power transmission. A microwave rectifier is designed and fabricated for the evaluation process. In design, inverse Class-F theory has been applied. Rectifier's RF/DC conversion efficiency is set as a Figure Of Merit (FOM). This FOM is acquired for different modulation type and bandwidth, in condition of equivalent...
First imaging tests of a 4-channel RF coil using novel 41 cm-long dipole elements with an eigen-resonant shielding plate in a 7-Tesla magnetic resonance imaging (MRI) system are presented. The proposed 4-channel coil is loaded by a homogeneous phantom to model the human body. Gradient echo images on the transverse, sagittal and coronal planes are acquired in CP+ mode and compared to the more established...
An advanced class-S transmitter architecture using a tri-level envelope encoding is presented. With tri-level encoding based on a delta-sigma modulator (DSM), a coding efficiency is improved compared to the two-level case, and sampling frequency is lowered to 522.24 MHz, which leads to an enhanced system efficiency. An analog/RF interface block is designed to control the propagation delay of the envelope...
As one central part in polar modulators and polar transmitters the phase modulation of the RF carrier is typically realized by a two-point modulation of the RF digital phase locked loop (DPLL) generating the carrier. However, with increasing channel bandwidths, advanced modulation and channel access schemes the phase modulation suffers from several impairments such as digitally controlled oscillator...
Wireless power transfer using coupling in the near-field, in opposition to far-field, shows advantages concerning link efficiency, however the link performance is widely dependent on proper antenna positioning. The transmission of energy using a far-field link would be desirable in many applications, namely for powering biomedical devices placed inside the body. This paper presents results from a...
In this paper, a design of a 3D 2.45 GHz energy harvesting circuit also called rectenna is presented. The circuit is made on flexible polyester dielectric allowing 3D rectenna design. The realized circuit dedicated to anti-counterfeiting applications is stacked on wine bottles in order to test the product authenticity. Bending impact on antenna was tested in order to choose the best orientation. The...
In this study, numerical simulations have been carried out to show the importance of modeling the meniscus for in vitro theoretical and experimental dosimetry. A plane wave has been considered impinging from different directions on a Petri dish filled with 2 or 4 mL of culture medium at 0.9, 1.8, and 2.5 GHz. Results indicate that the meniscus has a significant effect on the distributions of power...
A calibration technique as well as measurement results for a 7 GHz Biosensor are presented. It is shown that the applied sensor structure can be calibrated by adjusting the phase of a sensing element's transmission S21. This is realized by slowing down the wave traveling a microstrip line serving as a reference in the differential sensor structure. The dielectric properties along with certain physical...
Distortion measurements in mm-wave systems are becoming increasingly important and sometimes in the context of more complete digitally modulated structures. As at lower frequencies, multisine and complex envelope techniques can yield useful insight but now with wider instantaneous bandwidths and hence a wider range of time constants that can be studied. Side-effects can include more complicated calibrations...
Based on a magnetic coupling, this paper presents a novel device for power generation by spurious electromagnetic emissions from compact fluorescent lamps. The proposed scavenger consists of a resonant loop and an RF-to-DC voltage converter. Results of experimental tests performed with a 30 W compact fluorescent lamp are reported and discussed. It is shown that 0.61 mW can be generated, thus demonstrating...
Digital predistortion (DPD) and Crest Factor Reduction (CFR) are applied separately in radio frequency power amplifiers (PAs) in general. This paper proposes a method to jointly optimize DPD and CFR. For a given model of predistorter our solution gives automatically the Peak to average power ratio (PAPR) reduction gain to be applied by the CFR module. Within the DPD module PAPRs of original input...
This paper presents a novel 90 GHz band RF transceiver using polarization-division duplex (PDD) technology. A PDD architecture is used for full-duplex communication in the single band. The RF transceiver can deliver 6 Gbps through six channels with a bandwidth of 3 GHz. The channel bandwidth is 500 MHz. A IF combining structure is used for multi-channel. To implement the system, a fourth-harmonically...
In FDD radios, the problem of Self Interference, where the transmitter's own noise and distortion can desensitize the receiver is traditionally solved by RF filtering. For bands with narrow duplex spacing, this selectivity comes at the cost of bulky filters and insertion loss with an associated power loss in the front end. Moreover, with the drive towards, cheaper, smaller, integrated duplexers and...
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