Compact Receiver Research Articles

Fault-Tolerant Wireless Power Transfer System With a Dual-Coupled LCC-S Topology

A dual-coupled inductor-capacitor-capacitor and series (LCC-S) compensated wireless power transfer (WPT) system with a compact receiver size is proposed in this paper to improve the misalignment performance and achieve fault tolerant operation as well as a stable output power. The compensation coil and the main coil are integrated as two decoupled unipolar coils on the transmitter side, while they are both coupled with the receiver coil. The two mutual inductances among the two decoupled coils and the receiver coil have opposite impacts on the output power when they both increase or decrease. Therefore, the output power can remain stable when the misalignment increases. The short- and open-circuit characteristics are analyzed, which demonstrates that the proposed topology can achieve both short- and open-circuit protection. A prototype was built and the experimental results verified the theoretical analysis and simulations. The system can deliver from 297 W to 321 W when the x-misalignment increases from 0 mm to 90 mm, with a dc-dc efficiency of 92.78% to 93.56%. The proposed WPT system can be used for the wireless charging of e-mobility scooters and autonomous underwater vehicles. The system can provide a stable output and can tolerate both short- and open-circuit faults at the output.

A Compact Spatial Free-Positioning Wireless Charging System for Consumer Electronics Using a Three-Dimensional Transmitting Coil

A compact spatial free-positioning wireless charging system with a novel three-dimensional (3D) transmitting (Tx) coil is proposed to charge consumer electronics in the working area. Because of the strengthened electromagnetic field generated by the proposed 3D Tx coil in the space, this system can charge consumer electronics wirelessly with great tolerance to positional and angular misalignments between the transmitter and receiver. Benefiting from the compact design of the 3D Tx coil, the system can be easily embedded in some corners of office furniture/cubic panels, which will not cause any extra working space consumption when charging devices. The inductor-capacitor-capacitor (LCC) compensation circuit on the Tx side can achieve constant current output, which is independent of load condition and can protect the transmitter. With the LCC compensation circuit, the MOSFETs of the H-bridge high-frequency inverter realized zero voltage switching (ZVS). The small-sized planar receiving (Rx) coil and series (S) compensation circuit is applied to achieve compact receiver design. The theoretical and experimental results show that the spatial free-positioning wireless charging prototype can transfer 5 W to the small-sized receiver in around 350 mm × 225 mm × 200 mm 3D charging area and achieve the highest efficiency of 77.9%.

An LCC-P Compensated Wireless Power Transfer System with a Constant Current Output and Reduced Receiver Size

Wireless Power Transfer (WPT) for autonomous underwater vehicles (AUVs) has been a research focus in recent years. This paper studies the inductor-capacitor-capacitor and parallel (LCC-P) compensation topology to achieve a compact receiver for AUVs. Unlike the series-series (SS) compensation topology, the LCC-P topology retains the advantages of the double-sided LCC topology and has a more compact receiver than the double-sided LCC topology with fewer elements used on the receiver side. The analytical model of such a WPT system is established to analyze the output power and transfer efficiency. The LCC-P topology has a higher efficiency compared to the SS topology due to the smaller conduction loss of the inverter. Moreover, a method of eliminating the DC filter inductor L0 is proposed to further decrease the size and weight of the receiver. The amplitude of the withstanding voltage on the receiver compensation capacitor without L0 is approximately decreased by 40% compared to that with L0. Both cases of with and without L0 have a constant current output and the peak efficiency without L0 is about 94%, which is 1% lower than that with L0. A prototype was built and the experimental results verified the theoretical analysis.

Integrated modeling of compact power lines

The aim of the research presented in the article is to develop methods and means for integrated modeling of compact expanded capacity power lines. Algorithms for determining modes of electrical energy systems were used based on phase coordinates based on application of elements models in form of lacelike equivalent networks with fully-meshed topology. These models and methods were implemented in Fazonord-APC software application, ensuring modeling of EES sta-tionary modes, and determining strengths of electromagnetic fields generated by power lines of different design. We demonstrate results of modes and electromagnetic fields modeling on routes of 220 kV compact overhead power supply lines (COPL) with horizontal positioning of wires. For the purpose of comparison, similar calculations were performed for a typical overhead power line (TOPL). The modeling results allowed to formulate the following conclusions: when overall sections of COPL and TOPL are equal, the losses of active power in compact OPL are significantly lower; thus, when transmitted power is 375 MW, the losses in COPL are reduced by 45% compared to a typical 220 kV OPL; at compact OPL receiver end a lower unsymmetry is observed; COPL ensure better electromagnetic safety conditions; electrical field strength at a height of 1.8 m for COPL axis is less than a similar index for TOPL by approximately 1.5 times; magnetic field in the same point is reduced to 60%.

Constant Current Charging and Maximum Efficiency Tracking Control Scheme for Supercapacitor Wireless Charging

Charging current and efficiency of a wireless power transfer system depend on the equivalent load resistance of supercapacitor load, which varies during charging. To achieve constant current (CC) charging and maximized efficiency under variable loads, control method that employs primary-side phase shift H-bridge inverter and secondary-side semiactive rectifier are proposed. The proposed secondary-side control method not only achieves CC charging, but also ensures no reactive impedance seen into the semiactive rectifier. Furthermore, the maximum efficiency tracking is based on searching the minimum system dc input current for any given output power. It is realized by phase shift H-bridge inverter that is controlled by the perturbation and observation algorithm. Simulation and experimental results validate the feasibility of the proposed control method. During CC charging of 3 A, the maximum efficiency is 81% and largest efficiency improvement is 15.2% at light load. The proposed control method improves the system performance and is suitable for the applications that require compact receiver and no wireless communication link between the transmitter and the receiver.

High Speed 2-D Photodetector Array for Space and Mode-Division Multiplexing Fiber Communications

We report a high-data-rate two-dimensional photodetector array (2D-PDA) operated over 10 GHz for compact receiver systems in multicore fiber (MCF), few-mode fiber (FMF), and FMF-MCF, which can be directly coupled to multiparallel beams from the MCF and FMF. The 2D-PDA (pixel size of 20–30 μm, pixel number of 32) were designed and characterized for the frequency response and crosstalk. In the on-wafer probing test, the averaged 3-dB bandwidth of 11.2 GHz and 19.8 GHz were measured for 30-μm and 20-μm pixels, respectively. In the MCF direct-coupling demonstration with the 2D-PDA, the selected 16 pixels could work well at 25 Gb/s (nonreturn-to-zero: NRZ). By using triangular-shape-aligned seven-core fiber and the square-shape-aligned seven cores in the 2D-PDA, the coupling efficiency and alignment tolerance were investigated for the universal MCF photoreceiver. In the demonstration of the mode-division multiplexing signal detection with 2D-PDA, the multiplexed three-mode signal with 20-Gbps quadrature phase-shift keying was directly coupled to the 2D-PDA. Through the electrical phase matching system with the multiple-input multiple-output function, the three-mode signal (20 Gbps in each mode) could be successfully detected and separated error-free.

A Wide-Band High-Gain Compact SIS Receiver Utilizing a 300- $\mu$W SiGe IF LNA

Low-power low-noise amplifiers integrated with superconductor–insulator–superconductor (SIS) mixers are required to enable implementation of large-scale focal plane arrays. In this work, a 220-GHz SIS mixer has been integrated with a high-gain broad-band low-power IF amplifier into a compact receiver module. The low noise amplifier (LNA) was specifically designed to match to the SIS output impedance and contributes less than 7 K to the system noise temperature over the 4–8 GHz IF frequency range. A receiver noise temperature of 30–45 K was measured for a local oscillator frequency of 220 GHz over an IF spanning 4–8 GHz. The LNA power dissipation was only 300 $\mu$ W. To the best of the authors’ knowledge, this is the lowest power consumption reported for a high-gain wide-band LNA directly integrated with an SIS mixer.

Adaptive Blind Postdistortion and Equalization of System Impairments for a Single-Channel Concurrent Dual-Band Receiver

Concurrent dual-band receivers use fewer RF components to flexibly receive signals in the dual bands. To further reduce the number of components, a compact concurrent dual-band receiver architecture has been demonstrated in this paper. It employs only a single down-conversion channel to down-convert the dual-band signals simultaneously. The down-converted signal is a relatively narrowband signal without the wide gap between the two bands. Hence, slower analog-to-digital converters can be adopted in the subsequent circuits to digitize the received signal. Due to the nonlinearity of the low-noise amplifier, there might be noticeable nonlinearity distortion and memory effects in the received dual-band signals. To ensure high signal quality, a blind postdistortion algorithm is proposed to cancel out the nonlinearity distortion in the two received signals adaptively. Subsequently, the blind finite-impulse response equalizers for each band are built based on the modified constant modulus algorithm and the decision-directed equalization method. In addition, the nonideal wireless channel response is also able to be compensated using the proposed algorithm. Experimental results have shown perfect postcompensation performances of the overall algorithms in the dual bands.

Robust Training Symbol Assisted Least Squares Estimation for Direct Conversion Receivers with Oscillator IQ-Imbalance

The direct conversion receiver is attractive for being able to provide low-cost and compact receiver design for wireless communications. However, the oscillator imbalance in the in-phase and quadrature components of its mixing sinusoid introduces additional self-image interference, which is a non-linear effect to the received signal. Relying on just one OFDM training symbol, we formulate the joint estimation of oscillator imbalance, DC offset, and channel response as a linear model. A low-complexity least squares (LS) estimation method is then proposed. The transformation matrix in our model is shown to be of full rank with probability 1, which allows our LS approach to be realizable for a variety of training OFDM symbols. Justified by simulation results, our method outperforms the other three LS methods in the literature.

Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm3. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.

Efficiency optimization of WPT system with a planar receiver for mobile applications

ABSTRACTThis letter presents a wireless power transfer (WPT) system with a planar receiver for mobile applications. The proposed WPT system includes a source coil, a transmitter spiral (Tx coil), a rectangular receiver coil (Rx coil), and a rectangular load coil. In order to make a compact receiver, the Rx coil is placed in front of the load coil with a gap of 2 mm. In addition, the relation between the transfer efficiency of WPT system and the capacitance value of Rx coil is established. Experimental results show that by optimizing the capacitor embedded in Rx coil, it is capable of achieving a very high transfer efficiency. With an optimized capacitor Cx = 785 pF on the Rx coil, the transfer efficiency of the proposed system is comparable to a WPT system using a metamaterial (MTM) array. The proposed WPT system operates at 6.78 MHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1817–1819, 2016

A Practical Design of X‐Band Receiver Front‐End in 65‐nm CMOS

A low-cost low-power area-efficient receiver front-end prototype for X-band applications is presented. The front-end primarily consists of 3 blocks: a single-ended input differential-output Low noise amplifier (LNA), a double balanced down-converter, and Inter-frequency (IF) buffers providing single-ended output. Including are also Low dropout regulators (LDO) and Electrostatic discharge (ESD) protection circuits coinciding with the forgoing blocks. Local oscillator (LO) frequency is chosen such that output signal locates in L/S-band for extending subsequent applications. Experimentally exhibiting a conversion gain of around 44dB with 7.5-dB Single-sideband (SSB) Noise figure (NF), the front-end totally draws 24mA from an external 3.3-V supply. Fabricated in a 65-nm CMOS technology, this compact receiver occupies an area of only 0.22mm 2 .

Watt-level wireless power transmission to multiple compact receivers

This paper reports an electrodynamic wireless power transmission (EWPT) system using a low-frequency (300 Hz) magnetic field to transmit watt-scale power levels to multiple compact receivers. As compared to inductively or resonantly coupled coils, EWPT facilitates transmission to multiple non-interacting receivers with little restriction on their orientation. A single 3.0 cm3 receiver achieves 1.25 W power transmission with 8% efficiency at a distance of 1 cm (350 mW/cm3 power density) from the transmitter. The same prototype achieves 9 mW at a distance of 9 cm. Moreover, we demonstrate simultaneous recharge of two wearable devices, using two receivers located in arbitrary positions and orientations.

MIMO Optical Wireless Communications Using ACO-OFDM and a Prism-Array Receiver

In this paper, we analyze the performance of a prism-array receiver in a multiple-input multiple-output (MIMO) intensity-modulated direct-detection optical wireless communication system. The elements of the MIMO channel matrix depend on the geometry of each prism and the orientation of the prism relative to the optical transmitter. An expression is derived for each channel gain as a function of the angle of the prism, the aspect ratio and area of the receiving surface of the prism, and the orientation and distance between the transmitter and receiver. Results are presented for the directionality and overall field of view (FOV) of a receiver comprising six prisms, showing that compact receivers can be designed, which combine well-conditioned channel matrices with wide FOVs. Simulation results are presented for a typical indoor visible light communication system where four light-emitting diode lights transmit information using asymmetrically clipped optical orthogonal frequency division multiplexing and linear equalizers are used in the receiver. It is shown that the overall bit error rate depends very strongly on the angle of the prisms and on the position of the receiver, but that a simple six-prism receiver can successfully decouple the four transmitted signals at typical receiver positions within the room.

Design and analysis of a novel concentrated photovoltaic–thermal receiver concept

Solar concentrators, which focus the sunlight on a small surface of solar cells, are a promising way of reducing expensive semiconductor area and thus also the energy generation costs of photovoltaics. This paper presents the design and the analysis of a concentrated photovoltaic (CPV) receiver for a linear Fresnel concentrator mirror module. The receiver is designed as hybrid concentrated photovoltaic–thermal (CPV-T) receiver, which enables simultaneous generation of power and heat in one compact receiver. Spectral splitting with selective absorptive media and thermal decoupling of heat carrier and solar cells improves the electrical efficiency. Computational fluid dynamics (CFD) simulations of various receiver-setups result in an electrical efficiency of the receiver up to 6.2% and a thermal efficiency of up to 61.2% at a specific selected operating design point. 62% of the wavelengths of the incoming solar spectrum between 500 to 1100 nm hit the solar cells.

30 GHz HTS Receiver Front-End Based on Monolithic Josephson Mixer

A compact, high-gain, and low-noise Ka band HTS Josephson junction-based receiver front-end module for wireless communication is presented in this paper. The front-end module consists of biasing circuits, a semiconductor low-noise amplifier, and a monolithic HTS circuit consisting of an Josephson mixer, bandpass and lowpass filters. The semiconductor LNA in the first stage is applied to achieve a low noise figure of the whole front-end module. Integration of the Josephson mixer with a number of HTS passive components on a single chip improves the coupling efficiency and reduces the connection losses between the components. The total dimension of the packaged front-end module is below 25 mm × 20 mm × 15 mm, which is very compact. Measurement result shows that the front-end module has an overall conversion gain around 40 dB, and a low noise figure close to 0 dB with an LO driving power around -38 dBm at 40 K.

Compact High-Responsivity Receiver Optical Subassembly With a Multimode-Output-Arrayed Waveguide Grating for 100-Gb/s Ethernet

We developed a compact receiver optical subassembly (ROSA) for 100-Gigabit Ethernet (100 GbE) using multimode-output-arrayed waveguide grating (MM-AWG) and arrayed photodiodes (PDs). The four-channel silica-based MM-AWG has low insertion loss of less than 1 dB. The back-side-illumined PD with maximized-induced current structure provides high responsivity of 0.95 A/W. To avoid the distortion of the responsivity spectrum due to poor coupling between the multimode beam and PD, we employ a racetrack shape for the active region of the PD. The optical coupling between the MM-AWG and lens-coupled PD is optimized in terms of the flattening ratio of the racetrack shape. The fabricated ROSA has high responsivity of over 0.7 A/W with a flat-top spectrum and obtains high environmental stability thank to its large assembly tolerance of over ± 4 μm. For 4 × 25−Gb/s signals after 10-km transmission, the minimum receiver sensitivity of the ROSA has a margin of 4.8 dB for the Ethernet standard. The transmission performance with a 100-GbE transmitter optical subassembly was also confirmed.

Heterogeneously Integrated PLC With Low-Loss Spot-Size Converter and Newly Developed Waveplate PBS for DC-DP-16QAM Receiver

Digital coherent transmission systems with multilevel and multicarrier modulation formats have been moving beyond 100-G systems. In this paper, we report a one-chip 400-G coherent receiver founded on a silica-based planar lightwave circuit (PLC) integration platform. To integrate a polarization beam splitter (PBS), two polarization rotators, four-optical hybrids, and 16 high-speed photodiodes (PDs) in one chip, we employed a 5%-Δ waveguide with a minimum bending radius of 300 μm, and the heterogeneous integration of InP-PDs. To achieve a compact receiver without any degradation in optical passive performance, we also investigated a three-branched spot size converter with a low loss and a high-fabrication tolerance and a waveplate type PBS with a high-polarization extinction ratio. Using these techniques, we fabricated a dual-carrier dual-polarization (DP) 16-level quadrature amplitude modulation (QAM) receiver PLC, and successfully demonstrated 32-Gbaud DP-16QAM signal demodulation for each channel.

Ultra-compact coherent receiver with serial interface for pluggable transceiver.

An ultra-compact integrated coherent receiver with a volume of 1.3 cc using a quad-channel transimpedance amplifier (TIA)-IC chip with a serial peripheral interface (SPI) is demonstrated for the first time. The TIA with the SPI and photodiode (PD) bias circuits, a miniature dual polarization optical hybrid, an octal-PD and small optical coupling system enabled the realization of the compact receiver. Measured transmission performance with 32 Gbaud dual-polarization quadrature phase shift keying signal is equivalent to that of the conventional multi-source agreement-based integrated coherent receiver with dual channel TIA-ICs. By comparing the bit-error rate (BER) performance with that under continuous SPI access, we also confirmed that there is no BER degradation caused by SPI interface access. Such an ultra-compact receiver is promising for realizing a new generation of pluggable transceivers.

Compact antenna array receiver for robust satellite navigation systems

A compact navigation receiver comprising a decoupled and matched four-element L1-band antenna array with an inter-element separation of a quarter of the free-space wavelength is presented in this paper. We investigate the impact of the decoupling and matching network on the robustness of the navigation receiver. It is observed that in order to achieve high robustness with a compact antenna array, it is necessary to employ a decoupling and matching network, particularly in case of three spatially separated interferers. Furthermore, we study the influence of the polarization impurity of the compact planar antenna array on the equivalent carrier-to-interference-plus-noise ratio (CINR) of the receiver when impinged with different numbers of diametrically polarized interference signals. It is shown that the higher-order modes possess strong polarization impurity, which may halve the available degrees-of-freedom for nulling in the presence of linear-polarized interferers, using a conventional null-steering algorithm. We verify the robustness of the designed compact receiver by means of a complete global-navigation-satellite-system demonstrator. It is shown that the maximum jammer power that is allowed us to maintain the CINR above 38 dBHz with three interferers can be improved by more than 10 dB if a decoupling and matching network is employed.