Rx Side Research Articles

A Novel Magnetic Coupler with PQI Cores for Wireless Power Transfer

The magnetic coupler is a key component of the wireless power transfer (WPT) system, which greatly affects the performance of the WPT. This paper proposes a novel magnetic coupler with ferrite PQI cores for the WPT of small drones, which can enhance the magnetic coupling and improve power transfer efficiency. This magnetic coupler includes the transmitting (TX) side and receiving (RX) side. The TX side is made of a helical coil and a ferrite PQ core; and the RX side is made of a helical coil and a ferrite I core plate. Finite element simulations are used to investigate the performance of the proposed magnetic coupler with PQI cores, and compare it with a conventional planar magnetic coupler with two I core plates. In addition, an experimental platform is built to prove the validity of the proposed magnetic coupler with PQI cores. The results show that the coupling coefficient can reach 0.97, and it can exceed 0.446 even under the worst coupling conditions. Meanwhile, power transfer efficiency increases by 10.3% using the magnetic coupler with PQI cores.

A 6.78-MHz Wireless Power Transfer System With Inherent Wireless Phase Shift Control Without Feedback Data Sensing Coil

This article presents a 6.78-MHz wireless power transfer (WPT) system with a differential class-D power amplifier (PA) for the transmitter (TX) and a delay-tuned rectifier for the receiver (RX). Besides the RX local voltage regulation, we propose a fully integrated TX global power regulation with wireless phase shift control without any extra off-chip components. Furthermore, the proposed system eliminates the feedback data-sensing coil used in prior arts, thus greatly improving the system integration level and reducing the circuit complexity. On the TX side, the global loop regulates the transmitted power through the duty cycle control of 1X/2X operation modes of the class-D PA to improve the system efficiency over a wide load range. On the RX side, we realize ac–dc power rectification and voltage regulation with a delay-tuned rectifier. The TX and RX chips fabricated in a standard 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m CMOS process used 3.3-V devices. Measured results show that the circuit can obtain a system efficiency improvement up to 14.2% at light load conditions, with the proposed wireless phase shift control regulating the TX global power. The peak end-to-end system efficiency is 77%, and the maximum output power is 0.9 W with a 3.3-V output voltage.

Frequency-Modulation-Based IPT With Magnetic Communication for EV Wireless Charging

In this article, a switching frequency-modulation-based inductive power transfer system that provides wireless charging of the scooters by magnetic in-band communication is newly proposed. Although the transmitter (Tx) and receiver (Rx) coils are misaligned, the scooters can be freely charged in the charging station by the proposed frequency modulation method without additional power converters in the Tx and Rx sides. In order to implement frequency modulation control, the Rx side can transmit the required information to the Tx side through the magnetic coupling between Tx and Rx coils, i.e., magnetic in-band communication, in the suggested approach. By virtue of the proposed magnetic in-band communication method, the switching frequency can be modulated so that the load power for charging the battery in the Rx side is appropriately controlled, considering the battery charging profile. Contrary to the Qi standard technology using both amplitude shift keying (ASK) and frequency shift keying, the proposed magnetic communication protocol is optimally and simply designed for targeting scooter wireless charging applications. Because the proposed communication method is based on only ASK technique for unidirectional information delivery, the coil misalignment sensitivity and the complexity of the communication process can be reduced, which guarantees the robust frequency modulation control for load power regulation. A 100 W power level prototype for the charging station and the scooters was fabricated and verified by simulations and experiments. The 97.3% of the coil-to-coil efficiency and 90.6% of the dc-to-dc efficiency were obtained at a nominal operating point of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> = <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nom</sub> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P_L</i> = 100.8 W. As a result, the battery having 44.0–53.0 V and 13 Ah in the Rx side was charged under a wide range of battery charging conditions and coil misalignments.

Precise Modeling for Reducing Output Voltage Control Error of RX-Sensorless IPT System

This paper presents RX-Sensorless technologies required in a self-induced type of low power wireless power transfer system. Recently, apart from the fields of smartphone and electrical vehicles which have been arduously studied for application of wireless power transfer, wireless power transfer technologies are being applied to various fields. Among them, there is a very rapidly increasing demand for low power systems in displays, body implant medical devices, drones, electrical kickboards and so on. In order to acquire portability of RX side of low power systems, the most critical factors are power density and efficiency. For this purpose, there have been very much ongoing studies to improve the power density on the RX side. Among various research, most frequently used types of methods involve derivation of output voltage using the physical quantity on the TX side while removing sensors on the RX side. However, in the modeling process to derive output voltage, they fail to properly reflect the parasite components of wireless power transfer and also due to the lack of measures in case of being out of the range of resonance frequency, there tends to be a high error in the output voltage which raises an issue. Therefore, this paper aims to suggest a model which reflects the parasite resistance components and the permeability rate of medium for the TX/RX pads of wireless power transfer systems. By reflecting winding losses and eddy current losses of TX/RX pads to a model, it is possible to reflect the parasite resistance components and using the Neumann formula, it is possible to reflect it to the medium between RX/TX pads. As a result, based on the derived model, it is possible to control the output voltage. Prototypes of hardware are designed and implemented for verifications. According to the computer simulation results and test results, output voltage estimates yield an error in the range of less than or equal to 8% and model-based output voltage control also shows the control range with errors of less than or equal to 5%.

(Digital Presentation) Sub-THz Front Ends for Future Communication and Sensing Technologies in 130nm Sige Bicmos Technology

Introduction: Beyond the-5G technologies are targeting the available bandwidth (BW) in the D-band and J-band. This promises for very high speed communication and sensing accuracy. Although the advantages of operating beyond 100 GHz from the application point of view, it requires a lot of research and development to design a reliable and power efficient chipsets. In this presentation we will go through the design of wideband 240 GHz transmitter (Tx) and receiver (Rx). Firstly an overview about the link budget analysis will be given, then the design of the local carrier signal generator will be discussed. The wideband Txs and Rxs are to be presented with frequency channelizing concept. At the end the results of the wireless links will be demonstrated. Link Budget Analysis: Operating at sub-THz frequencies approaching the transistor fT put a lot of constraints on the system link budget. The elevated noise figure together with the limited maximum Pout of the transistors lead to solutions which might be limited in BW or power efficiency. Hence the design architecture need to be optimized taking into account the elevated power consumption and heat dissipation. Carrier Generation: Several approaches could be followed to generate the sub-THz carrier frequency. For a power efficient solution the fundamental oscillators promise for a power efficient solution but with limited phase noise performance and tuning range. Such a solution is more common for imaging systems operating at a single frequency. In order to achieve wider tuning ranges for multi-channel scenario or FMCW radar systems, the frequency multiplication chains are common, whereas the multiplication factor depends on the system parameters. Sub-THz Rx: Different approaches were followed to realize a wideband sub-THz Rx. For some technologies the transistors ft does not promise the realization of low noise amplifiers (LNA) with reasonable noise figure, gain and BW. Hence the mixer first approach were followed trying to optimize the noise figure of the down conversion mixer as much as possible. This also enhances the input compression point (IP1dB) of the Rx which is better for monostatic radar applications. On the other hand, if the technology in use allows the development of well performing LNA’s, the LNA first approach was followed to enhance the all over NF of the receiver and ease the implementation of IQ Rxs. In our work an LNA was implemented followed by IQ downconversion mixers and baseband chain as presented in [3]. Sub-THz Tx: The Tx main challenging performance parameter in the sub-THz frequency range is to achieve high output compression point across the required BW with as high efficiency as possible. Increasing the power handling capabilities of the power amplifiers (PA) by increasing the transistors sizes of the output stages, leads to low output impedance and hence higher impedance transformation ratios for the matching structures and eventually narrow band designs. Hence the power combining architectures were proposed as an alternative to increase the output power either by combining on-chip or combining in air. In this work a fully integrated IQ Tx is to be presented with on-chip LO chain and 4-way power combined power amplifier. Baseband Signal Generation and Processing The baseband topology depend on the application. For mobile communication or localization use cases a wideband channels are not available directly from the digital processors, a kind of channel bonding is required either in the digital domain or in the analog domain. As a proof of concept we present here 3-IQ frequency interleaving combiner. Wireless Link Demonstrator Two demonstrators are to be presented. The first demonstrator is transmitting a broadband IQ signal generated from an arbitrary wave generator wirelessly utilizing an IQ 240GHz Tx and Rx. Data rates up to 100 Gbps were demonstrated across a 1m of wireless link. The second demonstrator includes the implementation of 3-channel IQ channelizer to create the complex modulated signal at several intermediate frequencies (IFs) and then upconverted to the 240GHz carrier signal. On the Rx side the de-channelizer convert the down modulated signal to three IQ channels. Data rates up to 8Gbps were demonstrated wirelessly with the channelization with potential of further enhancements for more channels integration. Outlook The future of the sub-THz wireless links for high speed communication and localizations goes towards implementing phased array and MIMO systems. This requires the research community to develop novel architectures to develop large scale arrays with acceptable power consumptions and suitable packaging solution. On the baseband side also the channel bonding solutions are still in an early stage, requiring more work to bond modularly larger number of channels.

Accurate Method for Extracting the Coupling Coefficient of an LCC-Series Wireless Power Transfer System

This article proposes a method of extracting the coupling coefficient and the resonant frequency of the receiving (Rx) side of a wireless power transfer system with an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> -series topology, using only information from the transmitting (Tx) side. The proposed method has three modes, which allow the Tx coil and the Rx coil inductance and the coupling coefficient to be extracted, respectively. The coupling coefficient can be calculated while considering the tolerance of the coils. The Rx side senses the frequency of the Rx coil current, which is equal to the operating frequency of the inverter. This indicates that which mode the system is in, and the circuit on the Rx side is then modified to fit each mode. Details of the proposed method were analyzed using calculations, and simulations and experiments confirmed the effectiveness of the proposed method. Results showed that the coupling coefficient of the WPT system can be extracted with an error of less than 8%. In addition, the resonant frequency of the Rx side was accurately predicted, and then used as the operating frequency of the WPT system. Up to a 4% increase in efficiency was confirmed in the 80-W-class WPT experiment.

Compensation and monitoring of transmitter and receiver impairments in 10,000-km single-mode fiber transmission by adaptive multi-layer filters with augmented inputs.

We propose an adaptive multi-layer (ML) filter architecture to compensate for linear impairments that occur in transmitter (Tx) and receiver (Rx) components in ultra-long-haul optical fiber transmission systems, in which large chromatic dispersion (CD) accumulates in the received signal. The architecture consists of strictly linear (SL) and widely linear (WL) filter layers, and the coefficients of the ML filters are adaptively controlled by gradient calculation with back propagation and stochastic gradient descent. Static CD compensation is performed on the received signal and its complex conjugate before the adaptive ML filters. These augmented signals are then the inputs of the first 2×1 SL filter layer of the ML filters, for compensation of in-phase (I) and quadrature (Q) impairments on the Rx side. Tx IQ impairments and polarization effects as well as Rx IQ impairments are adaptively compensated in the ML filters. By sweeping CD compensation filters before the ML filters, this architecture mitigates the computational complexity for back propagation of the ML filters especially for ultra-long-haul transmission, while mutual non-commutativity between the WL filter for IQ impairment compensation and the CD compensation filter is appropriately solved. We evaluated the proposed adaptive ML filter architecture with augmented inputs through both simulation and wavelength-division multiplexed transmission experiments of 32-Gbaud polarization-division-multiplexed 64-quadrature amplitude modulation-based probabilistic constellation shaped signals over 10,000 km of single-mode fiber (SMF). The results demonstrated that the proposed adaptive ML filter architecture effectively compensates for Tx and Rx IQ skews in ultra-long-haul SMF transmission, and that impairments can be monitored individually from the converged filter coefficients of the corresponding layers.

Single-Receiver Multioutput Inductive Power Transfer System With Independent Regulation and Unity Power Factor

Inductive power transfer (IPT) systems with multiple output voltages are potential to supply a variety of loads simultaneously. This article proposes an IPT system with multiple semiactive rectifier cells (SARCs) connected in series at the receiver (Rx) side. These SARCs are independent of each other and their output voltages can be regulated individually with single receiver coil, which reduces the cost and volume. The proposed IPT configuration has the advantages of high flexibility, simple control, and no cross regulation. Considering that the SARC may cause additional reactance and lead to detuning of the Rx side, variable inductor is introduced to ensure the full tuning condition. Thus, the proposed IPT system can maintain zero phase angle operation with unity power factor in the whole load range, minimizing the reactive power losses. In addition, both primary inverter and the SARCs can achieve zero voltage switching. To verify the feasibility and validity of the proposed IPT system, an experimental prototype with two outputs of 640 W/150 V and 400 W/120 V is built.

Effective capacity analysis of SIMO system with MRC and SC over Inverse-Gamma shadowing

ABSTRACT Multiple antennas are usually employed to improve the performance of the wireless communication system. To this context, we derive the effective capacity (EC) expressions for Inverse Gamma (I-Gamma) shadowed fading channel, employing maximal ratio combining (MRC) and selection combining (SC) diversity schemes at the receiver (Rx) side. The channels are assumed to be independent and identical distributed (i.i.d.). In addition to this, we also propose the simplified high-power approximation that enables direct interpretation of the system performance concerning system fading parameters. Furthermore, to diminish the effect of shadowing over composite statistics, macroscopic diversity analysis is presented as an application, where Weibull, and I-Gamma models are used to obtain composite statistics. At last, we validate our proposed formulations through the Monte-Carlo simulation.

A study about signal variation with minor receiver displacement in a meeting room at 60\xa0GHz: measurements and simulations

The aim of this work is to study the impact of small receiver displacement on a signal propagation in a typical conference room environment at a millimeter wave frequency of 60 GHz. While channel measurements provide insights on the propagation phenomena, their use for the wireless system performance evaluation is challenging. Whereas, carefully executed three-dimensional ray tracing (RT) simulations represent a more flexible option. Nevertheless, a careful validation of simulation methodology is needed. The first target of this article is to highlight the benefits of an in-house built three-dimensional RT tool at 60 GHz and shows the effectiveness of simulations in predicting different characteristics of the channel. To validate the simulation results against the measurements, two different transmitter (Tx) positions and antenna types along with ten receiver (Rx) positions are considered in a typical conference room. In first system configuration, an omnidirectional antenna is placed in the middle of the table, while in the second system configuration a directed horn antenna is located in the corner of the meeting room. After validating the simulation results with the measurement data, in the second part of this work, the impact of a small change, i.e., 20 cm in the receiver position, is studied. To characterize the impact, we apply as performance indicators the received power level, root mean square delay spread (RMS-DS) and RMS angular spread (RMS-AS) in azimuth plane. The channel characteristics are considered with respect to the direct orientation (DO), i.e., the Rx antenna is directed toward the strongest incoming path. Different antenna configurations at the Tx and Rx side are applied to highlight the role of antenna properties on the considered channel characteristics. Especially, in the second system configuration the impact of different antenna half power beamwidth on different considered channel characteristics is highlighted through acquired simulation results. The validation of results shows the RMS error of only 2–3 dB between the measured and simulated received power levels for different Tx configurations in the direction of DO. Results indicate that only a small change of the Rx position may result a large difference in the received power level even in the presence of line-of-sight between the Tx and Rx. It is found that the STD of received power level across the room increases with the decrease in HPBW of the antenna. As can be expected, directed antennas offer lower value of RMS-DS and RMS-AS compared with isotropic antenna.

Construction of compressive measurement matrix based on sinusoidal function called Sinusoidal Sensing Matrix (SSM)

Compression sensing theory enables a safe reconstruction of signals under certain conditions. Random measurement (sensing) matrix Φ is one of the necessary conditions which give a strong impact on the behavior of the method used to reconstruct the signal. A deterministic method is therefore proposed to construct a new matrix called Sinusoidal Sensing Matrix (SSM) for compressing sensing theorem. The SSM matrix depends on its built upon generating equation used both Sin and Cos function depend upon the number of compressed samples. This new matrix is very simple and easy to create but very effective and can be generated in transmission and distention end without a need to send it, only need in Rx side knowledge of signal length. The new matrix interval meets the Restricted Isometry Property (RIP) characteristic with high probability.The simulation experiments of one- and two- dimensional signals, using a new matrix show a superior in evaluating recovered signals with parameters and the visual effect of the restored images.

Individually Regulated Dual-Output IPT System Based on Current-Mode Switching Cells

Based on the current-mode switching cell (CMSC), an inductive power transfer (IPT) system with dual-output is proposed in this letter. In the proposed IPT system, two CMSCs are inversely connected in series at the Rx side. Two CMSCs operate in the positive half-cycle and in the negative half-cycle of the Rx coil current, respectively. The dual output voltages can be regulated independently. The circuit structure of the CMSC is quite simple and helps to make the Rx side more compact. The control scheme is based on Rx-side real-time regulation and thereby wireless communication links are not required. Additionally, zero voltage switching is ensured for all switches. In order to verify the theoretical analysis, an experimental prototype with 20 V/3.3 A and 5 V/3 A outputs is fabricated, and the maximum efficiency can reach 92.8%.

Design of a New Hybrid Topology of WPT System to Achieve Load-Independent Constant-Current and Constant-Voltage Output

The usage of the Wireless Power Transfer (WPT) technique for charging lithium-ion (Li-ion) batteries of electric vehicles (EVs) is increasing rapidly. The Li-ion battery requires constant current (CC) followed by constant-voltage (CV) supply for efficient battery charging and to enhance its lifespan. However, it is hard to obtain CC and CV outputs due to the variation of battery resistance during charging. Moreover, a zero-phase angle (ZPA) of the input source is essential to improve the power transfer capability. Therefore, this paper proposes a new hybrid compensation topology to achieve load-independent CC and CV behavior of the WPT system along with ZPA. Two symmetrical coils have been used in the proposed WPT system as transmitter (Tx) and receiver (Rx) coils. A comprehensive mathematical analysis for achieving CC and CV characteristics as well as for power losses is carried out. A new hybrid compensation is designed by combining Series–Series (SS) and Inductor–Capacitor–Capacitor/Series (LCC-S) compensation topologies along with two additional switches. The proposed compensation works on single resonance frequency, and it is simple, reliable, and easy to implement with only one compensation capacitor from the Rx side. Simulations are performed, and a prototype is fabricated to verify the mathematical analysis and simulation results. The overall result shows that the mathematical analysis and simulations comply with the experimental results. Full load efficiencies of 90.33% and 88.91% are achieved in the CC and CV modes, respectively.

Adaptive and secure VCSEL FSO based on simple dual-polarized architecture for short distance transmission

In this study, using dual-polarized-multiplexing VCSEL based free space optical (FSO) transmission system is demonstrated experimentally. Two orthogonal polarizers (POLs), a beam splitter (BS) and a reflected mirror (M) are applied in the FSO transmitter (Tx) side to combine dual FSO signals into one for data security without code encryption. In the receiver (Rx) side, two blended FSO channels can be decoded adaptively by applying a POL with properly polarization status. Furthermore, when we add two corresponding POLs with orthogonal polarization in the Rx side, the FSO capacity also can double by the presented dual-polarized FSO architecture. Here, the relationships of the detected FSO powers and rotating angle between two POLs are also experimentally discussed.

Integrated Self-Adaptive and Power-Scalable Wideband Interference Cancellation for Full-Duplex MIMO Wireless

A wideband analog/RF interference cancellation technique that is able to autonomously adapt itself to timevarying interference channels and to scale its dc power based on the number of multiple-input-multiple-output (MIMO) array elements is presented. Least-mean square (LMS) adaptive circuitry is co-designed with and partially embedded in a wideband RF/analog interference canceller and a gain-boosted mixer-first receiver (RX), significantly reducing the system complexity and dc power while achieving rapid (microsecond-scale) adaptation. In addition, the proposed canceller is able to digitally adjust its transconductance and coupling strength at the RX side, essentially trading its dc power with the element-level RX noise figure (NF). At the array level, the NF can be lowered by averaging uncorrelated noise across elements. A prototype 0.5-to2.5-GHz full-duplex (FD) MIMO RX is designed and fabricated using a 65-nm CMOS process. With the adaptive circuitry fully integrated and consuming 14 mW, the cancellers adapt themselves to an unknown channel in 1 μs, providing >20-dB RF/analog interference cancellation across 20-MHz bandwidth (BW) with antenna voltage-standing-wave ratio (VSWR) up to 2:1. Simultaneous selfand cross-interference cancellation in our FD MIMO RX is also demonstrated using the integrated adaptation circuitry, achieving 24-dB overall interference cancellation across 20-MHz BW. The FD MIMO RX with selfand cross-interference cancellation is power-scalable-the NF-power scalability of the FD RX enables a nearly constant canceller dc power per element, despite a quadratic increase of cancellers.

A QPSK 110-Gb/s Polarization-Diversity MIMO Wireless Link With a 220–255 GHz Tunable LO in a SiGe HBT Technology

In this article, a polarization-diversity technique multiple-input multiple-output (MIMO) is demonstrated to double the spectral efficiency of a line-of-sight quadrature phase-shift keying (QPSK) wireless link at 220-255 GHz with a pair of highly integrated single-chip transmitter (TX) and receiver (RX) front-end modules in 0.13-μm SiGe HBT technology ( f T/ f max = 350/550 GHz) exploiting only a low-cost wire-bonded chip-on-board packaging solution for high-speed baseband (BB) signals. Both TX and RX chips accommodate two independent fundamentally operated direct-conversion in-phase and quadrature (IQ) paths with separately tunable on-chip multiplier-based (×16) local oscillator (LO) generation paths driven from a single external highly stable 13.75-16-GHz frequency synthesizer. On the RX side, a mixer-first architecture is implemented to improve the symmetry between upper and lower sidebands (USB and LSB) at the cost of an increased noise figure (NF), whereas, on the TX chip, each upconversion mixer is followed by a gain-bandwidth (BW)-limited fourstage power amplifier (PA) to support the link budget at a meter distance. Next, two independent IQ data streams from the upconversion/downconversion paths on each chip are directed to a common lens-coupled broadband on-chip slot antenna system. This way, two orthogonal circular polarizations [left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP)] can be transmitted with sufficient isolation for link operation without the need for a high-speed depolarizer in the BB for any relative orientation between TX and RX modules. The antenna combined with a 9-mm diameter Si-lens provides a directivity of 23.5-27 dBi at 210-270 GHz for each of the modules. This, along with a peak radiated power of 7.5 dBm/ch from the TX module, and the cascaded conversion gain (CG)/single sideband (SSB) NF of 18/18 dB/ch for the RX module followed by a broadband amplifier (PSPL5882) from Tektronix allowed successful transmission of two independent QPSK data streams with an aggregate speed of 110 and 80 Gb/s over 1 and 2 m, respectively, at 230 GHz with a board-level limited channel BB bandwidth (BW) of 13.5 GHz.

Distance estimation methods for a practical macroscale molecular communication system

Accurate estimation of the distance between the transmitter (TX) and the receiver (RX) in molecular communication (MC) systems can provide faster and more reliable communication. In addition, distance information can be used in determining the location of the molecular source in practical applications such as monitoring environmental pollution. Existing theoretical models in the literature are not suitable for distance estimation in a practical scenario. Furthermore, deriving an analytical model is a nontrivial problem, since the liquid in the TX is sprayed as droplets rather than molecules, these droplets move according to Newtonian mechanics, the size of the droplets change during their propagation and droplet-air interaction causes unsteady flows. Therefore, five different practical methods comprising three novel data analysis based methods and two supervised machine learning (ML) methods, Multivariate Linear Regression (MLR) and Neural Network Regression (NNR), are proposed for distance estimation at the RX side. In order to apply the ML methods, a macroscale practical MC system, which consists of an electric sprayer without a fan, alcohol molecules, an alcohol sensor and a microcontroller, is established, and the received signals are recorded. A feature extraction algorithm is proposed to utilize the measured signals as the inputs in ML methods. The numerical results show that the ML methods outperform the data analysis based methods in the root mean square error sense with the cost of complexity. The nearly equal performance of MLR and NNR shows that the input features such as peak time, peak concentration and the energy of the received signal have a highly linear relation with the distance. Moreover, the peak time based estimation, which is one of the proposed data analysis based methods, yields better results with respect to the other proposed four methods, as the distance increases. Given the experimental data and fluid dynamics theory, a possible trajectory of the molecules between the TX and RX is given. Our findings show that distance estimation performance is jointly affected by unsteady flows and the non-linearity of the sensor. According to our findings based on fluid dynamics, it is evaluated that fluid dynamics should be taken into account for more accurate parameter estimation in practical macroscale MC systems.

A 9 Gb/s/ch Transceiver With Reference-Less Data-Embedded Pseudo-Differential Clock Signaling for Graphics Memory Interfaces

A 9 Gb/s/ch transceiver with a reference-less data-embedded pseudo-differential clock signaling (RDCS) for graphics memory interfaces is proposed in a 65-nm CMOS technology. In the RDCS transceiver, the output data is embedded into differential clock signal by adopting a multi-level amplitude modulation in the transmitter (TX), and the data is recovered by extracting the data information from clock signal without reference clock in the receiver (RX) side. Because the data is synchronized with the clock at the TX, the received data can be recovered without DLL in the RX side. In addition, the additional pins required in the graphics memory interfaces can be removed by applying the proposed RDCS. The proposed design achieves less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> bit error rate with 9 Gb/s/ch data rate, and measured jitter in the recovered clock is 1.42 psRMS. In addition, the power efficiencies of the TX and RX are 2.33 and 1.03 pJ/bit, respectively.

Evaluation of input power splitting wireless power transfer system with multiple transmitters for efficiency maximisation

In a wireless power transfer (WPT) system, the efficiency decreases as the distance (DIS) or misalignment (MIS) between transmitter (Tx) coil and receiver (Rx) coil increases. As a result, the received load power is varying under different DIS/MIS conditions. Increasing the system efficiency and maintaining constant/stable output voltage/power are the major control targets in WPT system. This paper presents the evaluation of input power splitting (IPS) WPT system with multiple Tx coils (MTxWPT) in order to extend the area of output voltage/power stabilisation under varying DIS and MIS conditions, while improving the system efficiency at the same time. The control algorithm is realised by adaptively optimising the IPS multipliers α 1 through αn to unequally split the input power (P 1 through Pn ) between multiple Tx coils. The maximum system efficiency point can be achieved with the optimum selection of IPS multipliers (α 1 through αn ). A DC–DC converter at Rx side is utilised to maintain the output voltage/power at a constant/stable value. Detailed sets of the model analysis and experimental prototype results are provided and discussed through the paper to evaluate the performance of the presented IPS MTxWPT system.

Packaging Solution Based on Low-Temperature Cofired Ceramic Technology for Frequencies Beyond 100 GHz

In this paper, a package concept based on low-temperature cofired ceramic (LTCC) technology is illustrated. The concept is specifically designed for frequencies beyond 100 GHz, taking into consideration the inherent LTCC manufacturing defects, e.g., shrinkage, layer misalignment, and warping. Simple techniques are used for package assembly which can be automated using standard industrial processes. The proposed concept is implemented by integrating a 122-GHz silicon-germanium (SiGe) radar transceiver chip in an LTCC-based package. The off-chip components of the package, operating at 122 GHz, include a transmit (Tx) and a receive (Rx) aperture-coupled patch antenna array, a stripline to grounded coplanar waveguide signal transition feeding each of the antenna arrays, and three parallel, self-matched ground-signal-ground wirebonds connecting the SiGe radar transceiver chip and the LTCC package on Tx and Rx side. The simulation and measurement results of the Tx and Rx antenna arrays along with the signal transitions in the frequency range of 110–140 GHz are shown. The radar front end (RFE) is encapsulated using an epoxy molding compound, Polytec TC 430-T with suitable dielectric characteristics in the desired frequency range. The encapsulated RFE is surface mounted on a baseband printed circuit board, thereby realizing a fully functional 122-GHz frequency modulated continuous wave (FMCW) radar. The FMCW radar is used to measure the distance of a target, and the measurement results are compared with those of a commercial 122-GHz RFE.